Mixed-species exhibits with zoo-housed Hippopotamuses (Hippopotamidae)

 

 

Written by KRISZTIÁN SVÁBIK

Team Leader, Toni’s Zoo, Rothenburg, Lucerne, Switzerland

 

15th June 2022

 

INTRODUCTION

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Mixed-species exhibits with different mammals in the last few decades became a major trend. The success of a mixed-species exhibit depends on how we can take general animal husbandry criteria into account in more complex ways in comparison with a single-species exhibit. Those general rules that are important in animal exhibitry are still valid to a greater extent when presenting a multi-species captive environment. As many articles and other publications deal with the subject of general advantages and disadvantages of the mixed-species exhibits, instead of this, here I will assemble a detailed list of mixed exhibits involving at least one member of Hippopotamidae. The main aim of these documents is to summarize data and experiences about this exhibitry type with the hope that these manuals will be a useful supplement for the husbandry guidelines of both species of hippopotamids. Furthermore the study partly focuses on negative experiences in order to improve exhibit management criteria and trying to avoid combinations that have not been proved as successful.

The most important aspects of a successful mixed exhibit are the purposeful use of space and enclosure furnishings, the appropriate feeding techniques, decision-making of which species we want to breed and the right choice of species and individuals.

 

Use of space and enclosure furnishings

 

Generally speaking, one of the most critical factors is the size of the area: the larger the enclosure, the fewer the problems. Expanding the size of the whole captive habitat we can greatly increase the chances that the specimens of the different species are able to get out of each other’s way. Although this quantitative factor is also important, the quality of the given enclosure is much more crucial, since these agents can ensure the stress-free socialization of the combined species. It is extremely important to provide a secure outdoor and indoor space for the subdominant specimens whether belonging to the same species or not. The outdoor exhibit should be well-structured with many kinds of enclosure furnishing elements like small mounds, logs, rock formations and heavily planted areas so that the animals can get out of visual contact with others sharing the same enclosure and provide several escape routes in case of an aggressive contact between the different species. The best option is if the subdominant species have their own areas both outdoors and indoors.

 

Feeding

 

In terms of the daily routine tasks using the appropriate feeding techniques is one of the key factors of success. The experiences show that in several cases the associated species can be easily competitors of each other in reference to nutrition. Therefore it is necessary to feed the smaller species separately or provide as many feeding stations as possible throughout the whole enclosure and keep the competition to a minimum level, because most of the injuries and fatal accidents are the results of food-related aggression. In general, feeding the different species separately is a participating factor to manage the mixed-species exhibit successfully, but on the other hand this makes it difficult to apply certain food-related environmental enrichment methods in comparison with a single-species enclosure.

 

Breeding

 

One of the most important questions is to decide whether we would like to breed the species involved in a multi-species exhibit, or which species we want to breed. The practice of zoos keeping hippopotamids in a mixed exhibit shows that the presence of these large animals means potential danger for the other species when they are dominant in the given coexistence. Providing the abovementioned own areas or total separation can be the solution during the time of rearing the young. Furthermore, the behavioural changes of the adult animals during the breeding season must also be borne in mind which may easily lead to fatal injuries. Therefore it is really important to emphasize the possibility of proper separation. Generally speaking it seems to be true that the proper management of breeding in a mixed-species enclosure is more difficult – or sometimes impossible – than in a single-species exhibit. As a result, there is no aim to breed (all) the animals in this type of exhibitry in many cases, so sterilisation and single-sex grouping are also applied techniques in managing. If any of the species has an important breeding programme like SSP or EEP, it is worth to look over and analyse all the mentioned disadvantages before putting the given animals into a mixed enclosure.

 

Choice of species and individuals

 

According to the criteria of species selection, most of the known examples show that zoos exhibit animals together from the same geographic region for educational purposes. In the case of combining species that occupy similar ecological niches in nature the level of competition can be very high, therefore a large difference in body size between the combined species may be part of the solution. Choosing animals with different lifestyles – for example terrestrial-arboreal or diurnal-nocturnal – might be a good option as well. Although considering the theoretical approaches of the appropriate selection of species are also very important, we have to take into account that the success of the combination depends mostly on the individual level, simply because of the diverse individual characteristics of the animals in terms of behaviour. Correct introduction of the different species is a very sensitive issue which depends principally on the method of socialization and age of the animals. Introducing the smaller and subdominant species to the exhibit can be efficient due to exploring the whole area. During the socialization the principle of gradience should be followed, so visual and olfactory stimuli have to be the first before the possibility of physical contact of the animals. In general younger animals can be combined easier, but the experiences have shown us that many adults hippopotamid specimens have successfully been mixed with several other taxa.

 

List of mixed-species exhibits involving Hippopotamids

 

This document purposefully focuses on creating a list of mixed-species exhibits with family Hippopotamidae, for further and detailed information it is worth contacting the institutions mentioned below. Only a short summary of the general experiences is given at the end of the document. Many of the listed coexistences are still ongoing at present, but many of them are not anymore.

 

In the list below you can see that both species of hippopotamids have been kept in mixed exhibits in captivity:

 

Hippopotamuses, Hippopotamidae

 

Hippopotamus, Hippopotamus amphibius LINNAEUS, 1758

Pygmy Hippopotamus, Choeropsis liberiensis MORTON, 1849

 

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Mutualism, as a didactic concept in mixed-species exhibitry

 

 

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Studies have shown that many African birds have been observed to help groom Hippopotamuses by feeding on insects and parasites from the hippo’s back. The most frequently observed bird species are the Common Sandpiper (Actitis hypoleucos), African Pied Wagtail (Motacilla aguimp), Yellow-billed Oxpecker (Buphagus africanus) and Red-billed Oxpecker (Buphagus erythrorynchus) (OLIVIER & LAURIE 1974). Hippopotamuses and oxpeckers are in a mutualistic and parasitic relationship: this is because the oxpecker gets food and protection from the hippo, however, the bird gets food by making little cuts in the Hippopotamus to obtain insects.

Although these birds feed mainly on ticks, several studies have reported that oxpeckers can feed on wounded tissue, mucus, saliva, ear wax, hair and blood as well (BEZUIDENHOUT & STUTTERHEIM 1980, WEEKS 1999, PLANTAN 2009). Some authors definitely think that the interaction between oxpeckers and their mammalian hosts is parasitism, while others support mutualism even though they admit oxpeckers can cause injuries to hosts (SAMISH & REHACEK 1999). In fact the relationship between oxpeckers and large African herbivores could be context-dependent, where birds can be opportunists under particular biotic and abiotic conditions (NUNN et al. 2011, PLANTAN 2009). For example, a mutualistic relationship may develop when the ectoparasite load is high on the host, but oxpeckers may become parasitic when hosts carry few ticks with too many birds, and this leads to numerous open wounds (GAGNON et al. 2019).

The Common Sandpiper has often been reported on the backs of hippos (RICE 1963, THOMSON 1964) foraging from there for aquatic organisms. POOLEY (1967) gives further records of birds fishing off hippos, although CURRY-LINDAHL (1961) records 28 species of birds associating with Hippopotamuses (OLIVIER & LAURIE 1974). It is also worth mentioning that Hippopotamuses have commensally beneficial associations with birds and often they will use the backs of hippos as fishing sites. In nature species of stork, spoonbill, egret and heron – i.e. Goliath Heron (Ardea goliath) – have been observed on a regular basis – and further species such as Little Grebe (Tachybaptus ruficollis), Whistling-duck (Dendrocygna sp.), Egyptian Goose (Alopochen aegyptiaca) and Spur-winged Goose (Plectropterus gambensis) on a less regular basis – looking for plant material that Hippopotamuses displace (ELTRINGHAM 1999).

In zoo environment the mutualistic relationship between Red-billed Oxpecker and large African herbivores could be observed in the former Africa House in Zoo Zürich, where the birds lived together with Hippopotamuses, Southern White Rhinoceroses (Ceratotherium simum simum) and Eastern Black Rhinoceroses (Diceros bicornis michaeli) inside the building.

Those birds which are associated with Hippopotamuses in their natural habitat – i.e. herons, egrets, storks, spoonbills, geese and ducks – can also be seen together with hippos in captivity, many zoological institutions serve as examples for that.

Another important and definitely mutualistic relationship should be mentioned: it has long been known that different species of fish and Hippopotamuses are constant symbiotic companions. Fish clean hippos and are in turn nourished by the algae, parasites and dead skin scraped from the hides of their hosts. The amazing thing is that certain fish species specialize in cleaning specific body parts of the hippos. The Labeo – which is genus of carps – is the main cleaner, using its wide rasping mouth to scour the hippo’s hide. Barbus feeds on dung and cleans the cracks in the soles of the feet. Small cichlids graze around the tail bristles and tiny Garra clean out the wounds. Hippos deliberately splay their toes and spread their legs to provide easy access to the fish. The hippos even visit places where fish congregate in order to solicit cleanings (JOHNSON 2019). The African Cichlids – e.g. those live in Lake Malawi and Lake Victoria – together with another freshwater fish, e.g. different species of Tilapia, feed off the dung of the hippos, while the African Carp (Labeo coubie) feed on the dead skin as it flakes from the Hippopotamus, keeping their bodies clean.

On the other hand, a study was published in 2018 in reference to how the hippos’ presence in the Mara River in East Africa impacts other aquatic creatures and this research shows that vast numbers of fish were being killed downstream by hippo faeces (DUTTON et.al. 2018).

On the basis of the mutualism described above several zoological institutions place African Cichlids in the pond of their Hippopotamus exhibits not only because they both exist in their wild habitats together, but because would like to demonstrate their natural symbiotic relationship where different fish clean the hippos’ bodies which then provides them with a great source of nutrition and additionally help to improve the water quality of the pool.

 

Hippopotamuses (Hippopotamus amphibius) and Lake Malawi Cichlids (Cichlidae)

San Antonio Zoo, San Antonio, Texas, United States of America

Photo © Len Radin

 

Young Hippopotamus (Hippopotamus amphibius) and Nile Tilapias (Oreochromis niloticus)

Cincinnati Zoo & Botanical Garden, Cincinnati, Ohio, United States of America

Photo © Lisa Hubbard

 

LIST OF SPECIES COMBINATIONS - HIPPOPOTAMIDAE

 

The list shows examples of species combinations with at least one hippopotamus species combined with the taxa below

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 Hippopotamus, Hippopotamus amphibius (Photo © Krisztián Svábik)

Asian Elephant, Elephas maximus

African Elephant, Loxodonta africana

Geoffroy's Spider Monkey, Ateles geoffroyi

Vervet Monkey, Chlorocebus pygerythrus

Capybara, Hydrochoerus hydrochaeris

Cape Porcupine, Hystrix africaeaustralis

Egyptian Fruit Bat, Rousettus aegyptiacus

Rodrigues Flying Fox, Pteropus rodricensis

California Sea Lion, Zalophus californianus

Plains Zebra, Equus quagga

Grant’s Zebra, Equus quagga boehmi

Chapman’s Zebra, Equus quagga chapmani

Grevy’s Zebra, Equus grevyi

Southern White Rhinoceros, Ceratotherium simum simum

Dromedary Camel, Camelus dromedarius

Common Warthog, Phacochoerus africanus

Southern Warthog, Phacochoerus africanus sundevallii

Red River Hog, Potamochoerus porcus

Pygmy Hippopotamus, Choeropsis liberiensis

Chital, Axis axis

Hog Deer, Axis porcinus

Central European Red Deer, Cervus elaphus hippelaphus

Nyala, Tragelaphus angasii

Bushbuck, Tragelaphus scriptus

Southern Bushbuck, Tragelaphus scriptus sylvaticus

Western Sitatunga, Tragelaphus spekii gratus

Greater Kudu, Tragelaphus strepsiceros

Common Eland, Tragelaphus oryx

Addax, Addax nasomaculatus

Red Hartebeest, Alcelaphus buselaphus caama

Blesbok, Damaliscus pygargus phillipsi

Waterbuck, Kobus ellipsiprymnus ellipsiprymnus

Defassa Waterbuck, Kobus ellipsiprymnus defassa

Red Lechwe, Kobus leche leche

Nile Lechwe, Kobus megaceros

Common Impala, Aepyceros melampus melampus

Springbok, Antidorcas marsupialis

Thomson's Gazelle, Eudorcas thomsonii

Fringe-eared Oryx, Oryx beisa callotis

Scimitar-horned Oryx, Oryx dammah

Arabian Oryx, Oryx leucoryx

Roan Antelope, Hippotragus equinus

Sable Antelope, Hippotragus niger niger

Common Wildebeest, Connochaetes taurinus

Eastern White-bearded Wildebeest, Connochaetes taurinus albojubatus

Cape Buffalo, Syncerus caffer

Ankole-Watusi Cattle, Bos primigenius f. taurus

Domesticated Water Buffalo, Bubalus arnee f. bubalis

South African Giraffe, Giraffa camelopardalis giraffa

Reticulated Giraffe, Giraffa camelopardalis reticulata

Rothschild's Giraffe, Giraffa camelopardalis rothschildi

Ostrich, Struthio camelus

North African Ostrich, Struthio camelus camelus

South African Ostrich, Struthio camelus australis

Masai Ostrich, Struthio camelus massaicus

Dalmatian Pelican, Pelecanus crispus

Great White Pelican, Pelecanus onocrotalus

Pink-backed Pelican, Pelecanus rufescens

Great Cormorant, Phalacrocorax carbo

White-breasted Cormorant, Phalacrocorax lucidus

Great White Egret, Ardea alba

Goliath Heron, Ardea goliath

Cattle Egret, Bubulcus ibis

Hamerkop, Scopus umbretta

Abdim’s Stork, Ciconia abdimii

White Stork, Ciconia ciconia

Yellow-billed Stork, Mycteria ibis

African Openbill, Anastomus lamelligerus

Saddle-billed Stork, Ephippiorhynchus senegalensis

Marabou, Leptoptilos crumenifer

African Spoonbill, Platalea alba

White Ibis, Eudocimus albus

Glossy Ibis, Plegadis falcinellus

Hadada Ibis, Bostrychia hagedash

Southern Bald Ibis, Geronticus calvus

African Sacred Ibis, Threskiornis aethiopicus

Greater Flamingo, Phoenicopterus roseus

African Comb Duck, Sarkidiornis melanotos

Black-bellied Whistling-duck, Dendrocygna autumnalis

Fulvous Whistling-duck, Dendrocygna bicolor

White-faced Whistling-duck, Dendrocygna viduata

Ruddy Shelduck, Tadorna ferruginea

Egyptian Goose, Alopochen aegyptiaca

Blue-winged Goose, Cyanochen cyanoptera

Northern Pintail, Anas acuta

Cape Teal, Anas capensis

Red-billed Teal, Anas erythrorhyncha

Mallard, Anas platyrhynchos

Yellow-billed Duck, Anas undulata

White-eyed Duck, Aythya australis

Tufted Duck, Aythya fuligula

Marbled Teal, Marmaronetta angustirostris

Southern Pochard, Netta erythrophthalma

White-headed Duck, Oxyura leucocephala

American Black Vulture, Coragyps atratus

Palm-nut Vulture, Gypohierax angolensis

Hooded Vulture, Necrosyrtes monachus

White-headed Vulture, Trigonoceps occipitalis

Helmeted Guineafowl, Numida meleagris

Domestic Chicken, Gallus gallus f. domestica

Common Coot, Fulica atra

Purple Swamphen, Porphyrio porphyrio

Grey Crowned-crane, Balearica regulorum

South African Grey Crowned-crane, Balearica regulorum regulorum

Wattled Crane, Bugeranus carunculatus

White-bellied Bustard, Eupodotis senegalensis

Spur-winged Lapwing, Vanellus spinosus

Brown-faced Go-away-bird, Corythaixoides personatus

Taveta Golden Weaver, Ploceus castaneiceps

Village Weaver, Ploceus cucullatus

Red-billed Oxpecker, Buphagus erythrorynchus

Aldabra Giant Tortoise, Aldabrachelys gigantea

Black-bellied Slider, Trachemys dorbigni

African Cichlids, Cichlidae

Zebra Tilapia, Heterotilapia buettikoferi

Nile Tilapia, Oreochromis niloticus

Spotted Tilapia, Pelmatolapia mariae

Common Carp, Cyprinus carpio

Grass Carp, Ctenopharyngodon idella

Northern Pike, Esox lucius

Black Pacu, Colossoma macropomum

Green Swordtail, Xiphophorus hellerii

Saltan Fish, Leptobarbus rubripinna

other fish

 

 

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 Pygmy Hippopotamus, Choeropsis liberiensis (Photo © Krisztián Svábik)

African Elephant, Loxodonta africana

Saddleback Tamarin, Leontocebus fuscicollis

Red-chested Mustached Tamarin, Saguinus labiatus

Goeldi’s Monkey, Callimico goeldii

White-faced Saki, Pithecia pithecia

Northern Talapoin Monkey, Miopithecus ogouensis

Sykes’s Monkey, Cercopithecus albogularis

Red-tailed Monkey, Cercopithecus ascanius

Diana Monkey, Cercopithecus diana

Blue Monkey, Cercopithecus mitis

Stuhlmann's Blue Monkey, Cercopithecus mitis stuhlmanni

Mona Monkey, Cercopithecus mona

De Brazza’s Monkey, Cercopithecus neglectus

Spot-nosed Monkey, Cercopithecus petaurista

Roloway Monkey, Cercopithecus roloway

Wolf's Monkey, Cercopithecus wolfi

Sooty Mangabey, Cercocebus atys

Red-capped Mangabey, Cercocebus torquatus

Barbary Macaque, Macaca sylvanus

Drill, Mandrillus leucophaeus

Mandrill, Mandrillus sphinx

Angolan Colobus, Colobus angolensis

Peters' Angolan Colobus, Colobus angolensis palliatus

Guereza, Colobus guereza

Silvery Gibbon, Hylobates moloch

Sumatran Orangutan, Pongo abelii

Western Lowland Gorilla, Gorilla gorilla gorilla

Serval, Leptailurus serval

Plains Zebra, Equus quagga

Grant’s Zebra, Equus quagga boehmi

Grevy’s Zebra, Equus grevyi

Southern White Rhinoceros, Ceratotherium simum simum

Northern White Rhinoceros, Ceratotherium simum cottoni

Black Rhinoceros, Diceros bicornis

Eastern Black Rhinoceros, Diceros bicornis michaeli

Red River Hog, Potamochoerus porcus

Hippopotamus, Hippopotamus amphibius

Southern Pudu, Pudu puda

Mountain Bongo, Tragelaphus eurycerus isaaci

Sitatunga, Tragelaphus spekii

East African Sitatunga, Tragelaphus spekii spekii

Western Sitatunga, Tragelaphus spekii gratus

Greater Kudu, Tragelaphus strepsiceros

Common Eland, Tragelaphus oryx

East African Eland, Tragelaphus oryx pattersonianus

Addax, Addax nasomaculatus

Topi, Damaliscus korrigum jimela

Bontebok, Damaliscus pygargus pygargus

Waterbuck, Kobus ellipsiprymnus

Defassa Waterbuck, Kobus ellipsiprymnus defassa

Kob, Kobus kob

Uganda Kob, Kobus kob thomasi

Southern Lechwe, Kobus leche

Red Lechwe, Kobus leche leche

Kafue Lechwe, Kobus leche kafuensis

Nile Lechwe, Kobus megaceros

Common Impala, Aepyceros melampus

Thomson's Gazelle, Eudorcas thomsonii

Slender-horned Gazelle, Gazella leptoceros

Dama Gazelle, Nanger dama

Grant's Gazelle, Nanger granti

Scimitar-horned Oryx, Oryx dammah

Fringe-eared Oryx, Oryx beisa callotis

Gemsbok, Oryx gazella

Roan Antelope, Hippotragus equinus

Angolan Roan Antelope, Hippotragus equinus cottoni

Common Wildebeest, Connochaetes taurinus

Eastern White-Bearded Wildebeest, Connochaetes taurinus albojubatus

Cape Buffalo, Syncerus caffer

Aoudad, Ammotragus lervia

Red-flanked Duiker, Cephalophus rufilatus

Cape Blue Duiker, Philantomba monticola monticola

Congo Blue Duiker, Philantomba monticola congica

Rothschild's Giraffe, Giraffa camelopardalis rothschildi

Ostrich, Struthio camelus

Great White Pelican, Pelecanus onocrotalus

Goliath Heron, Ardea goliath

Black-crowned Night-heron, Nycticorax nycticorax

Cattle Egret, Bubulcus ibis

Hamerkop, Scopus umbretta

White Stork, Ciconia ciconia

Yellow-billed Stork, Mycteria ibis

Marabou, Leptoptilos crumenifer

African Spoonbill, Platalea alba

Hadada Ibis, Bostrychia hagedash

Black Swan, Cygnus atratus

Mute Swan, Cygnus olor

Greylag Goose, Anser anser

Hawaiian Goose, Branta sandvicensis

Egyptian Goose, Alopochen aegyptiaca

Fulvous Whistling-duck, Dendrocygna bicolor

African Black Duck, Anas sparsa

Hartlaub's Duck, Pteronetta hartlaubii

Rüppell's Vulture, Gyps rueppelli

Domestic Helmeted Guineafowl, Numida meleagris f. domestica

Blue Crane, Anthropoides paradiseus

Grey Crowned-crane, Balearica regulorum

Violet Turaco, Musophaga violacea

African Grey Hornbill, Lophoceros nasutus

Red-billed Hornbill, Tockus erythrorhynchus

Jackson's Hornbill, Tockus jacksoni

Trumpeter Hornbill, Bycanistes bucinator

Grey-cheeked Hornbill, Bycanistes subcylindricus

Speckled Mousebird, Colius striatus

Lilac-breasted Roller, Coracias caudatus

Bearded Barbet, Pogonornis dubius

Eastern Yellow-billed Barbet, Trachylaemus purpuratus

Eastern Black-headed Oriole, Oriolus larvatus

Purple Starling, Lamprotornis purpureus

Superb Starling, Lamprotornis superbus

Cape White-eye, Zosterops virens

Buff-throated Sunbird, Chalcomitra adelberti

Olive Sunbird, Cyanomitra olivacea

Green-headed Sunbird, Cyanomitra verticalis

Red-tailed Bristlebill, Bleda syndactylus

Blue-shouldered Robin-chat, Cossypha cyanocampter

Green Twinspot, Mandingoa nitidula

Grey-headed Nigrita, Nigrita canicapillus

White-headed Buffalo-weaver, Dinemellia dinemelli

Black-billed Weaver, Ploceus melanogaster

African Spurred Tortoise, Centrochelys sulcata

African Softshell Turtle, Trionyx triunguis

African Cichlids, Cichlidae

Zebra Tilapia, Heterotilapia buettikoferi

Spotted Tilapia, Pelmatolapia mariae

Nile Perch, Lates niloticus

Common Carp, Cyprinus carpio

Koi, Cyprinus carpio f. domestica

Grass Carp, Ctenopharyngodon idella

African Catfish, Clarias gariepinus

other fish

 

 

LIST OF MIXED-SPECIES EXHIBITS WITH LOCATIONS - HIPPOPOTAMIDAE

 

The list shows specific examples of current and historic mixed-species exhibits involving at least one hippopotamus species combined with the taxa below, with indication of the institution(s) where they have been tried out

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 Hippopotamus, Hippopotamus amphibius

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Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Asian Elephant, Elephas maximus
• Domesticated Water Buffalo, Bubalus arnee f. bubalis
• Black-bellied Whistling-duck, Dendrocygna autumnalis
• White-faced Whistling-duck, Dendrocygna viduata
• Black-bellied Slider, Trachemys dorbigni

 

Institution(s): Zooparque Itatiba (Itatiba, São Paulo, Brazil)

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Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• African Elephant, Loxodonta africana
• Grant’s Zebra, Equus quagga boehmi
• Grevy’s Zebra, Equus grevyi
• Southern White Rhinoceros, Ceratotherium simum simum
• Greater Kudu, Tragelaphus strepsiceros
• Common Eland, Tragelaphus oryx
• Red Hartebeest, Alcelaphus buselaphus caama
• Common Impala, Aepyceros melampus
• Springbok, Antidorcas marsupialis
• Roan Antelope, Hippotragus equinus
• Cape Buffalo, Syncerus caffer
• Ankole-Watusi Cattle, Bos primigenius f. taurus
• Reticulated Giraffe, Giraffa camelopardalis reticulata
• Ostrich, Struthio camelus

 

Institution(s): Parque Zoológico Nacional (Havana, Cuba)

 

 

Hippopotamuses (Hippopotamus amphibius) and Grant’s Zebras (Equus quagga boehmi)

Parque Zoológico Nacional, Havana, Cuba

Photo © Hector Jozami

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Geoffroy's Spider Monkey, Ateles geoffroyi
• Capybara, Hydrochoerus hydrochaeris
• birds

 

Institution(s): Jardín Zoológico de la Habana (Havana, Cuba)

 

Hippopotamus (Hippopotamus amphibius) and Geoffroy's Spider Monkey (Ateles geoffroyi)

Jardín Zoológico de la Habana, Havana, Cuba

Photo © Nick Hadad

 

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Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Cape Porcupine, Hystrix africaeaustralis
• Cattle Egret, Bubulcus ibis
• Hamerkop, Scopus umbretta
• Abdim’s Stork, Ciconia abdimii
• Taveta Golden Weaver, Ploceus castaneiceps
• previously duck (assorted species)
• previously Purple Swamphen, Porphyrio porphyrio
• previously Crowned-crane, Balearica sp.
• previously White-bellied Bustard, Eupodotis senegalensis
• African Cichlids, Cichlidae

 

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Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Cape Porcupine, Hystrix africaeaustralis
• African Cichlids, Cichlidae

 

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Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Egyptian Fruit Bat, Rousettus aegyptiacus

 

Institution(s): Tiergarten Schönbrunn (Vienna, Austria)

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Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Rodrigues Flying Fox, Pteropus rodricensis
• Western Sitatunga, Tragelaphus spekii gratus
• previously Fulvous Whistling-duck, Dendrocygna bicolor
• White-faced Whistling-duck, Dendrocygna viduata (only indoor)
• Helmeted Guineafowl, Numida meleagris
• previously Grey Crowned-crane, Balearica regulorum
• Wattled Crane, Bugeranus carunculatus
• Nile Tilapia, Oreochromis niloticus

 

Institution(s): Kölner Zoo (Cologne, Germany)

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Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• California Sea Lion, Zalophus californianus

 

Institution(s): Longleat (Warminster, United Kingdom)

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Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Grant’s Zebra, Equus quagga boehmi
• Southern White Rhinoceros, Ceratotherium simum simum
• Common Eland, Tragelaphus oryx
• Defassa Waterbuck, Kobus ellipsiprymnus defassa
• Thomson's Gazelle, Eudorcas thomsonii
• Scimitar-horned Oryx, Oryx dammah
• Arabian Oryx, Oryx leucoryx
• Eastern White-bearded Wildebeest, Connochaetes taurinus albojubatus
• North African Ostrich, Struthio camelus camelus
• Pelican, Pelecanus sp.
• White Stork, Ciconia ciconia
• Marabou, Leptoptilos crumenifer
• Glossy Ibis, Plegadis falcinellus
• Greater Flamingo, Phoenicopterus roseus
• Egyptian Goose, Alopochen aegyptiaca
• Mallard, Anas platyrhynchos
• Common Coot, Fulica atra
• Grey Crowned-crane, Balearica regulorum
• Spur-winged Lapwing, Vanellus spinosus
• other birds

 

Institution(s): Zoological Center Tel Aviv – Safari Ramat Gan (Ramat Gan, Israel)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Grant’s Zebra, Equus quagga boehmi
• Southern White Rhinoceros, Ceratotherium simum simum
• Addax, Addax nasomaculatus
• South African Giraffe, Giraffa camelopardalis giraffa
• Masai Ostrich, Struthio camelus massaicus
• Marabou, Leptoptilos crumenifer

 

Institution(s): The Tisch Family Zoological Gardens – Jerusalem Biblical Zoo (Jerusalem, Israel)

 

Hippopotamus (Hippopotamus amphibius) and Grant's Zebra (Equus quagga boehmi)

The Tisch Family Zoological Gardens – Jerusalem Biblical Zoo, Jerusalem, Israel

Photo © Jerusalem Biblical Zoo

 

Hippopotamus (Hippopotamus amphibius) in a mixed-species exhibit

The Tisch Family Zoological Gardens – Jerusalem Biblical Zoo, Jerusalem, Israel

Photo © Alex Kantorovich

 

Hippopotamus (Hippopotamus amphibius) in a mixed-species exhibit

The Tisch Family Zoological Gardens – Jerusalem Biblical Zoo, Jerusalem, Israel

Photo © Wikimedia Commons

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Grant’s Zebra, Equus quagga boehmi
• Dromedary Camel, Camelus dromedarius
• Common Eland, Tragelaphus oryx
• Ostrich, Struthio camelus

 

Institution(s): Taronga Western Plains Zoo (Dubbo, New South Wales, Australia)

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Chapman’s Zebra, Equus quagga chapmani
• Common Warthog, Phacochoerus africanus
• Nyala, Tragelaphus angasii
• Greater Kudu, Tragelaphus strepsiceros
• Common Eland, Tragelaphus oryx
• Blesbok, Damaliscus pygargus phillipsi
• Waterbuck, Kobus ellipsiprymnus ellipsiprymnus
• Red Lechwe, Kobus leche leche
• Common Impala, Aepyceros melampus melampus
• Scimitar-horned Oryx, Oryx dammah
• Sable Antelope, Hippotragus niger niger
• Common Wildebeest, Connochaetes taurinus taurinus
• Ankole-Watusi Cattle, Bos primigenius f. taurus
• Rothschild's Giraffe, Giraffa camelopardalis rothschildi
• South African Ostrich, Struthio camelus australis
• Egyptian Goose, Alopochen aegyptiaca
• Helmeted Guineafowl, Numida meleagris
• South African Grey Crowned-crane, Balearica regulorum regulorum

 

Institution(s): Monde Sauvage Safari Parc (Aywaille, Belgium)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Plains Zebra, Equus quagga
• Common Eland, Tragelaphus oryx
• Cape Buffalo, Syncerus caffer
• Ankole-Watusi Cattle, Bos primigenius f. taurus
• other ungulates

 

Institution(s): ZooSafari de Thoiry (Thoiry, France)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Plains Zebra, Equus quagga
• Defassa Waterbuck, Kobus ellipsiprymnus defassa
• South African Ostrich, Struthio camelus australis

 

Institution(s): Taman Safari Indonesia (Bogor, Indonesia)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Grant’s Zebra, Equus quagga boehmi
• Ostrich, Struthio camelus

 

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Southern White Rhinoceros, Ceratotherium simum simum
• Nyala, Tragelaphus angasii
• Egyptian Goose, Alopochen aegyptiaca

 

Institution(s): Parco Natura Viva (Bussolengo, Italy)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Southern Warthog, Phacochoerus africanus sundevallii
• Chital, Axis axis
• Hog Deer, Axis porcinus
• Southern Bushbuck, Tragelaphus scriptus sylvaticus
• Red Lechwe, Kobus leche leche
• Common Impala, Aepyceros melampus
• Scimitar-horned Oryx, Oryx dammah

 

Institution(s): Bothongo Rhino & Lion Nature Reserve (Krugersdorp, South Africa)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Red River Hog, Potamochoerus porcus

 

Institution(s): Zoo du Bassin d'Arcachon (La Teste-de-Buch, France)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Pygmy Hippopotamus, Choeropsis liberiensis

 

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Central European Red Deer, Cervus elaphus hippelaphus
• other ungulates

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Nyala, Tragelaphus angasii
• Waterbuck, Kobus ellipsiprymnus ellipsiprymnus
• Common Impala, Aepyceros melampus melampus
• Pink-backed Pelican, Pelecanus rufescens
• Ruddy Shelduck, Tadorna ferruginea
• Egyptian Goose, Alopochen aegyptiaca
• Mallard, Anas platyrhynchos
• Helmeted Guineafowl, Numida meleagris

 

Institution(s): ZOO Dvůr Králové (Dvůr Králové nad Labem, Czech Republic)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Nyala, Tragelaphus angasii
• Egyptian Goose, Alopochen aegyptiaca
• other birds, i.e. Mallard, Anas platyrhynchos and Southern Pochard, Netta erythrophthalma
• fish, i.e. Grass Carp, Ctenopharyngodon idella

 

Institution(s): Zoologischer Garten Berlin (Berlin, Germany)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Bushbuck, Tragelaphus scriptus
• Aldabra Giant Tortoise, Aldabrachelys gigantea

 

Institution(s): Haller Park (Mombasa, Kenya)

 

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Western Sitatunga, Tragelaphus spekii gratus
• Nile Lechwe, Kobus megaceros
• Marabou, Leptoptilos crumenifer

 

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Western Sitatunga, Tragelaphus spekii gratus
• Saddle-billed Stork, Ephippiorhynchus senegalensis

 

Institution(s): ZOOM Erlebniswelt Gelsenkirchen (Gelsenkirchen, Germany)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Greater Kudu, Tragelaphus strepsiceros
• Sable Antelope, Hippotragus niger niger

 

Institution(s): Zoo du Bassin d'Arcachon (La Teste-de-Buch, France)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Ostrich, Struthio camelus

 

Institution(s): Zoo du Bassin d'Arcachon (La Teste-de-Buch, France)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Dalmatian Pelican, Pelecanus crispus
• Great Cormorant, Phalacrocorax carbo

 

Institution(s): ZOO Antwerpen (Antwerp, Belgium)

 

 

 

Hippopotamuses (Hippopotamus amphibius) and Dalmatian Pelican (Pelecanus crispus)

ZOO Antwerpen, Antwerp, Belgium

Photos © Tom van Deuren

 

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Great White Pelican, Pelecanus onocrotalus

 

Institution(s): Le PAL - Parc d’Attractions et Animalier (Saint-Pourçain-sur-Besbre, France)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Pink-backed Pelican, Pelecanus rufescens
• White-breasted Cormorant, Phalacrocorax lucidus
• Great White Egret, Ardea alba
• White Ibis, Eudocimus albus
• White-faced Whistling-duck, Dendrocygna viduata
• Egyptian Goose, Alopochen aegyptiaca
• Northern Pintail, Anas acuta
• Yellow-billed Duck, Anas undulata
• American Black Vulture, Coragyps atratus

 

Institution(s): Disney's Animal Kingdom Theme Park (Bay Lake, Florida, United States of America)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Pink-backed Pelican, Pelecanus rufescens
• Hamerkop, Scopus umbretta
• Abdim’s Stork, Ciconia abdimii
• Yellow-billed Stork, Mycteria ibis
• African Openbill, Anastomus lamelligerus
• African Spoonbill, Platalea alba
• Hadada Ibis, Bostrychia hagedash
• Southern Bald Ibis, Geronticus calvus
• African Sacred Ibis, Threskiornis aethiopicus
• African Comb Duck, Sarkidiornis melanotos
• Blue-winged Goose, Cyanochen cyanoptera
• Cape Teal, Anas capensis
• White-headed Duck, Oxyura leucocephala
• Palm-nut Vulture, Gypohierax angolensis
• Hooded Vulture, Necrosyrtes monachus
• White-headed Vulture, Trigonoceps occipitalis
• South African Grey Crowned-crane, Balearica regulorum regulorum
• fish, e.g. Common Carp, Cyprinus carpio, Grass Carp, Ctenopharyngodon idella, Northern Pike, Esox lucius

 

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Goliath Heron, Ardea goliath

 

Institution(s): Cleveland Metroparks Zoo (Cleveland, Ohio, United States of America)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Cattle Egret, Bubulcus ibis
• Hamerkop, Scopus umbretta
• White-faced Whistling-duck, Dendrocygna viduata
• Red-billed Teal, Anas erythrorhyncha
• Marbled Teal, Marmaronetta angustirostris
• Brown-faced Go-away-bird, Corythaixoides personatus
• Village Weaver, Ploceus cucullatus
• fish

 

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Cattle Egret, Bubulcus ibis
• Red-billed Oxpecker, Buphagus erythrorynchus

 

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Hamerkop, Scopus umbretta

 

Institution(s): København Zoo (Copenhagen, Denmark)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• African Sacred Ibis, Threskiornis aethiopicus

 

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• White-eyed Duck, Aythya australis
• Tufted Duck, Aythya fuligula

 

Institution(s): Disney's Animal Kingdom Theme Park (Bay Lake, Florida, United States of America)

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Domestic Chicken, Gallus gallus f. domestica

 

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• African Cichlids, Cichlidae

 

Institution(s): Saint Louis Zoo (Saint Louis, Missouri, United States of America) (with Zebra Tilapia, Heterotilapia buettikoferi and Spotted Tilapia, Pelmatolapia mariae), San Antonio Zoo (San Antonio, Texas, United States of America) (with Lake Malawi Cichlids), Disney's Animal Kingdom Theme Park (Bay Lake, Florida, United States of America) (with Lake Victoria Cichlids), Cincinnati Zoo & Botanical Garden (Cincinnati, Ohio, United States of America) (with Nile Tilapia, Oreochromis niloticus), ZooTampa at Lowry Park (Tampa, Florida, United States of America), BREC's Baton Rouge Zoo (Baton Rouge, Louisiana, United States of America), Memphis Zoo (Memphis, Tennessee, United States of America), San Diego Zoo (San Diego, California, United States of America), Calgary Zoo (Calgary, Alberta, Canada) (with Tilapia), Zoom Torino (Cumiana, Italy) (with Lake Malawi Cichlids), Erlebnis-Zoo Hannover (Hanover, Germany), Bioparc Valéncia (Valencia, Spain) (with Lake Malawi Cichlids)

 

Hippopotamus (Hippopotamus amphibius) and Lake Malawi Cichlids (Cichlidae)

San Antonio Zoo, San Antonio, Texas, United States of America

Photo © Nancy Merolle

 

Hippopotamus (Hippopotamus amphibius) and Nile Tilapia (Oreochromis niloticus)

Cincinnati Zoo & Botanical Garden, Cincinnati, Ohio, United States of America

Photo © Lisa Hubbard

 

Hippopotamuses (Hippopotamus amphibius) and Nile Tilapias (Oreochromis niloticus)

Cincinnati Zoo & Botanical Garden, Cincinnati, Ohio, United States of America

Photo © Robert Streithorst

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Common Carp, Cyprinus carpio
• Grass Carp, Ctenopharyngodon idella

 

---

 

Combined species:

 

• Hippopotamus, Hippopotamus amphibius
• Black Pacu, Colossoma macropomum
• Green Swordtail, Xiphophorus hellerii
• Saltan Fish, Leptobarbus rubripinna

 

Institution(s): Zoo Warszawa (Warsaw, Poland)

---

 

 

 Pygmy Hippopotamus, Choeropsis liberiensis

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• African Elephant, Loxodonta africana

 

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Saddleback Tamarin, Leontocebus fuscicollis
• Red-chested Mustached Tamarin, Saguinus labiatus
• Goeldi’s Monkey, Callimico goeldii

 

Institution(s): Zoologischer Garten Halle – Bergzoo (Halle, Germany)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• White-faced Saki, Pithecia pithecia

 

Institution(s): Zoologischer Garten Halle – Bergzoo (Halle, Germany)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Talapoin Monkey, Miopithecus sp.
• Sykes’s Monkey, Cercopithecus albogularis
• Red-tailed Monkey, Cercopithecus ascanius
• Sooty Mangabey, Cercocebus atys
• Red-capped Mangabey, Cercocebus torquatus
• Mandrill, Mandrillus sphinx
• Guereza, Colobus guereza
• birds (23 species): Cattle Egret, Bubulcus ibis, African Spoonbill, Platalea alba, Hadada Ibis, Bostrychia hagedash, Violet Turaco, Musophaga violacea, Red-billed Hornbill, Tockus erythrorhynchus, Jackson's Hornbill, Tockus jacksoni, Trumpeter Hornbill, Bycanistes bucinator, Grey-cheeked Hornbill, Bycanistes subcylindricus, Speckled Mousebird, Colius striatus, Lilac-breasted Roller, Coracias caudatus, Eastern Yellow-billed Barbet, Trachylaemus purpuratus, Eastern Black-headed Oriole, Oriolus larvatus, Superb Starling, Lamprotornis superbus, Cape White-eye, Zosterops virens, Buff-throated Sunbird, Chalcomitra adelberti, Olive Sunbird, Cyanomitra olivacea, Green-headed Sunbird, Cyanomitra verticalis, Red-tailed Bristlebill, Bleda syndactylus, Blue-shouldered Robin-chat, Cossypha cyanocampter, Green Twinspot, Mandingoa nitidula, Grey-headed Nigrita, Nigrita canicapillus, White-headed Buffalo-weaver, Dinemellia dinemelli, Black-billed Weaver, Ploceus melanogaster

 

Institution(s): Brookfield Zoo (Brookfield, Illinois, United States of America)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Red-tailed Monkey, Cercopithecus ascanius
• Blue Monkey, Cercopithecus mitis

 

Institution(s): Brookfield Zoo (Brookfield, Illinois, United States of America)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Red-capped Mangabey, Cercocebus torquatus
• Mandrill, Mandrillus sphinx
• Guereza, Colobus guereza

 

Institution(s): Brookfield Zoo (Brookfield, Illinois, United States of America)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Northern Talapoin Monkey, Miopithecus ogouensis
• previously Mona Monkey, Cercopithecus mona
• Drill, Mandrillus leucophaeus
• Western Sitatunga, Tragelaphus spekii gratus
• Great White Pelican, Pelecanus onocrotalus
• Egyptian Goose, Alopochen aegyptiaca
• African Black Duck, Anas sparsa
• fish

 

Institution(s): Bioparc Valéncia (Valencia, Spain)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Diana Monkey, Cercopithecus diana
• Zebra Tilapia, Heterotilapia buettikoferi
• Spotted Tilapia, Pelmatolapia mariae
• Nile Perch, Lates niloticus

 

Institution(s): Zoo Leipzig (Leipzig, Germany)

 

Pygmy Hippopotamus (Choeropsis liberiensis) and Diana Monkey (Cercopithecus diana)

Zoo Leipzig, Leipzig, Germany

Photo © Fabian Schmidt

 

Pygmy Hippopotamus (Choeropsis liberiensis) and Diana Monkeys (Cercopithecus diana)

Zoo Leipzig, Leipzig, Germany

Photo © William Bezodis

 

Pygmy Hippopotamus (Choeropsis liberiensis) and Spotted Tilapias (Pelmatolapia mariae)

Zoo Leipzig, Leipzig, Germany

Photo © Fabian Schmidt

 

Pygmy Hippopotamus (Choeropsis liberiensis), Zebra Tilapias (Heterotilapia buettikoferi) and Spotted Tilapias (Pelmatolapia mariae)

Zoo Leipzig, Leipzig, Germany

Photo © Ariel Jacken

 

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Diana Monkey, Cercopithecus diana
• De Brazza’s Monkey, Cercopithecus neglectus
• Wolf's Monkey, Cercopithecus wolfi
• African Softshell Turtle, Trionyx triunguis
• fish

 

Institution(s): Omaha’s Henry Doorly Zoo and Aquarium (Omaha, Nebraska, United States of America)

 

Pygmy Hippopotamus (Choeropsis liberiensis) and primates indoor mixed-species exhibit

Omaha’s Henry Doorly Zoo and Aquarium, Omaha, Nebraska, United States of America

Photo © Fabian Schmidt

 

Pygmy Hippopotamus (Choeropsis liberiensis) and primates indoor mixed-species exhibit

Omaha’s Henry Doorly Zoo and Aquarium, Omaha, Nebraska, United States of America

Photo © Josh Chamberlain

 

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Blue Monkey, Cercopithecus mitis

 

Institution(s): Omaha’s Henry Doorly Zoo and Aquarium (Omaha, Nebraska, United States of America)

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Stuhlmann’s Blue Monkey, Cercopithecus mitis stuhlmanni
• Angolan Colobus, Colobus angolensis
• African Softshell Turtle, Trionyx triunguis

 

Institution(s): Omaha’s Henry Doorly Zoo and Aquarium (Omaha, Nebraska, United States of America)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• De Brazza’s Monkey, Cercopithecus neglectus

 

Institution(s): Parc Zoologique de CERZA (Hermival-les-Vaux, France)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Roloway Monkey, Cercopithecus roloway

 

Institution(s): Parc Zoologique de CERZA (Hermival-les-Vaux, France)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Spot-nosed Monkey, Cercopithecus petaurista
• Wolf's Monkey, Cercopithecus wolfi
• African Cichlids, Cichlidae

 

Institution(s): San Diego Zoo (San Diego, California, United States of America)

 

Pygmy Hippopotamus (Choeropsis liberiensis) and Wolf's Monkey (Cercopithecus wolfi)

San Diego Zoo, San Diego, California, United States of America

Photo © Peter Csanadi

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Wolf's Monkey, Cercopithecus wolfi
• Red-flanked Duiker, Cephalophus rufilatus
• Cape Blue Duiker, Philantomba monticola monticola

 

Institution(s): San Diego Zoo (San Diego, California, United States of America)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Red-capped Mangabey, Cercocebus torquatus

 

Institution(s): Zoologischer Garten Halle – Bergzoo (Halle, Germany)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Barbary Macaque, Macaca sylvanus

 

unknown institution

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Mandrill, Mandrillus sphinx

 

Institution(s): South Lakes Safari Zoo (Lindal-in-Furness, United Kingdom), Zoologischer Garten Halle – Bergzoo (Halle, Germany), Bioparc Fuengirola (Fuengirola, Spain), Melbourne Zoo (Melbourne, Victoria, Australia)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Colobus, Colobus sp.

 

Institution(s): San Diego Zoo (San Diego, California, United States of America)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Peters' Angolan Colobus, Colobus angolensis palliatus
• Great White Pelican, Pelecanus onocrotalus

 

Institution(s): Zoologická a botanická zahrada města Plzně (Pilsen, Czech Republic)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Silvery Gibbon, Hylobates moloch

 

Institution(s): Zoologischer Garten Halle – Bergzoo (Halle, Germany)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Sumatran Orangutan, Pongo abelii

 

Institution(s): Taman Safari Indonesia (Bogor, Indonesia)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Western Lowland Gorilla, Gorilla gorilla gorilla

 

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Serval, Leptailurus serval

 

Institution(s): Bioparc Fuengirola (Fuengirola, Spain)

 

Pygmy Hippopotamus (Choeropsis liberiensis) and Servals (Leptailurus serval)

Bioparc Fuengirola, Fuengirola, Spain

Photo © Jonas Livet

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Grant’s Zebra, Equus quagga boehmi
• Grevy’s Zebra, Equus grevyi
• Northern White Rhinoceros, Ceratotherium simum cottoni
• Eastern Black Rhinoceros, Diceros bicornis michaeli
• East African Sitatunga, Tragelaphus spekii spekii
• East African Eland, Tragelaphus oryx pattersonianus
• Topi, Damaliscus korrigum jimela
• Defassa Waterbuck, Kobus ellipsiprymnus defassa
• Uganda Kob, Kobus kob thomasi
• Red Lechwe, Kobus leche leche
• Nile Lechwe, Kobus megaceros
• Common Impala, Aepyceros melampus
• Thomson's Gazelle, Eudorcas thomsonii
• Slender-horned Gazelle, Gazella leptoceros
• Grant's Gazelle, Nanger granti
• Fringe-eared Oryx, Oryx beisa callotis
• Angolan Roan Antelope, Hippotragus equinus cottoni
• Eastern White-Bearded Wildebeest, Connochaetes taurinus albojubatus
• Cape Buffalo, Syncerus caffer
• Rothschild's Giraffe, Giraffa camelopardalis rothschildi

 

Institution(s): San Diego Zoo Safari Park (Escondido, California, United States of America)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Grant’s Zebra, Equus quagga boehmi
• Greater Kudu, Tragelaphus strepsiceros
• Bontebok, Damaliscus pygargus pygargus
• Slender-horned Gazelle, Gazella leptoceros
• Dama Gazelle, Nanger dama
• Marabou, Leptoptilos crumenifer
• Grey Crowned-crane, Balearica regulorum

 

Institution(s): Montgomery Zoo and Mann Wildlife Learning Museum (Montgomery, Alabama, United States of America)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Plains Zebra, Equus quagga
• Ostrich, Struthio camelus

 

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Grevy’s Zebra, Equus grevyi
• Addax, Addax nasomaculatus
• Scimitar-horned Oryx, Oryx dammah
• Rothschild's Giraffe, Giraffa camelopardalis rothschildi
• Ostrich, Struthio camelus

 

Institution(s): Aalborg Zoo (Aalborg Zoo, Denmark)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Red River Hog, Potamochoerus porcus
• Addax, Addax nasomaculatus
• Domestic Helmeted Guineafowl, Numida meleagris f. domestica

 

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Red River Hog, Potamochoerus porcus
• Nile Lechwe, Kobus megaceros
• Domestic Helmeted Guineafowl, Numida meleagris f. domestica

 

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Hippopotamus, Hippopotamus amphibius

 

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Southern Pudu, Pudu puda

 

Institution(s): ZSL London Zoo (London, United Kingdom)

---

 

Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Mountain Bongo, Tragelaphus eurycerus isaaci
• Grey Crowned-crane, Balearica regulorum

 

Institution(s): Le Zoo de La Flèche (La Fléche, France)

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Sitatunga, Tragelaphus spekii

 

Institution(s): Réserve Zoologique de Calviac (Calviac-en-Périgord, France), Batu Secret Zoo (Batu, Indonesia)

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Kafue Lechwe, Kobus leche kafuensis
• Black Swan, Cygnus atratus
• Mute Swan, Cygnus olor
• Koi, Cyprinus carpio

 

Institution(s): Limassol Zoo (Limassol, Cyprus)

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Aoudad, Ammotragus lervia

 

Institution(s): Nyíregyházi Állatpark (Nyíregyháza, Hungary)

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Red-flanked Duiker, Cephalophus rufilatus

 

Institution(s): Houston Zoo (Houston, Texas, United States of America)

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Congo Blue Duiker, Philantomba monticola congica

 

Institution(s): Koninklijke Burgers' Zoo (Arnhem, the Netherlands)

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Great White Pelican, Pelecanus onocrotalus

 

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Goliath Heron, Ardea goliath (only indoor)

 

Institution(s): Zoologická a botanická zahrada města Plzně (Pilsen, Czech Republic)

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Goliath Heron, Ardea goliath
• Black-crowned Night-heron, Nycticorax nycticorax
• Cattle Egret, Bubulcus ibis
• White Stork, Ciconia ciconia
• Yellow-billed Stork, Mycteria ibis
• Marabou, Leptoptilos crumenifer
• African Spoonbill, Platalea alba
• Fulvous Whistling-duck, Dendrocygna bicolor
• other birds

 

Institution(s): Zoo du Bassin d'Arcachon (La Teste-de-Buch, France)

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Cattle Egret, Bubulcus ibis
• Hamerkop, Scopus umbretta
• Violet Turaco, Musophaga violacea
• African Grey Hornbill, Lophoceros nasutus
• Bearded Barbet, Pogonornis dubius
• White-headed Buffalo-weaver, Dinemellia dinemelli

 

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Hamerkop, Scopus umbretta
• Red-billed Hornbill, Tockus erythrorhynchus
• Purple Starling, Lamprotornis purpureus
• Superb Starling, Lamprotornis superbus
• African Catfish, Clarias gariepinus

 

Institution(s): Aalborg Zoo (Aalborg, Denmark)

 

Pygmy Hippopotamus (Choeropsis liberiensis) and African Catfish (Clarias gariepinus)

Aalborg Zoo, Aalborg, Denmark

Photo © Fabian Schmidt

 

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Marabou, Leptoptilos crumenifer

 

Institution(s): Givskud Zoo – Zootopia (Givskud, Denmark)

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Marabou, Leptoptilos crumenifer
• African Spurred Tortoise, Centrochelys sulcata

 

Institution(s): Xantus János Állatkert (Győr, Hungary)

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Greylag Goose, Anser anser

 

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Hawaiian Goose, Branta sandvicensis

 

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Egyptian Goose, Alopochen aegyptiaca

 

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Hartlaub's Duck, Pteronetta hartlaubii
• Rüppell's Vulture, Gyps rueppelli

 

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Hartlaub's Duck, Pteronetta hartlaubii
• fish

 

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Combined species:

 

• Pygmy Hippopotamus, Choeropsis liberiensis
• Blue Crane, Anthropoides paradiseus

 

List of zoological institutes with mixed-species exhibits involving Hippopotamids

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 Hippopotamus, Hippopotamus amphibius

 

Australia

Taronga Western Plains Zoo, Dubbo, New South Wales, Australia

Austria

Tiergarten Schönbrunn, Vienna, Austria

Belgium

Monde Sauvage Safari Parc, Aywaille, Belgium

Pairi Daiza, Brugelette, Belgium

ZOO Antwerpen, Antwerp, Belgium

Brazil

Zooparque Itatiba, Itatiba, São Paulo, Brazil

Canada

Calgary Zoo, Calgary, Alberta, Canada

Cuba

Jardín Zoológico de la Habana, Havana, Cuba

Parque Zoológico Nacional, Havana, Cuba

Czech Republic

ZOO Dvůr Králové, Dvůr Králové nad Labem, Czech Republic

Denmark

København Zoo, Copenhagen, Denmark

France

Parc Le PAL, Dompierre-sur-Besbre, France

Zoo du Bassin d'Arcachon, La Teste-de-Buch, France

ZooParc de Beauval, Saint-Aignan, France

ZooSafari de Thoiry, Thoiry, France

Germany

Erlebnis-Zoo Hannover, Hanover, Germany

Kölner Zoo, Cologne, Germany

Zoologischer Garten Berlin, Berlin, Germany

ZOOM Erlebniswelt Gelsenkirchen, Gelsenkirchen, Germany

Indonesia

Taman Safari Indonesia, Bogor, Indonesia

Israel

The Tisch Family Zoological Gardens – Jerusalem Biblical Zoo, Jerusalem, Israel

Zoological Center Tel Aviv – Safari Ramat Gan, Ramat Gan, Israel

Italy

Parco Natura Viva, Bussolengo, Italy

Safari Ravenna, Ravenna, Italy

Zoom Torino, Cumiana, Italy

Kenya

Haller Park, Mombasa, Kenya

Netherlands

Safaripark Beekse Bergen, Hivarenbeek, the Netherlands

WILDLANDS Adventure Zoo Emmen, Emmen, the Netherlands

Poland

Zoo Warszawa, Warsaw, Poland

ZOO Wrocław, Wrocław, Poland

Russia

Yekaterinburgskiy Zoopark, Yekaterinburg, Russia

South Africa

Bothongo Rhino & Lion Nature Reserve, Krugersdorp, South Africa

Spain

Bioparc Valéncia, Valencia, Spain

Switzerland

Zoo Basel, Basel, Switzerland

Zoo Zürich, Zürich, Switzerland

United Kingdom

Longleat, Warminster, United Kingdom

United States of America

Adventure Aquarium, Camden, New Jersey, United States of America

BREC's Baton Rouge Zoo, Baton Rouge, Louisiana, United States of America

Cheyenne Mountain Zoo, Colorado Springs, Colorado, United States of America

Cincinnati Zoo & Botanical Garden, Cincinnati, Ohio, United States of America

Cleveland Metroparks Zoo, Cleveland, Ohio, United States of America

Disney's Animal Kingdom Theme Park, Bay Lake, Florida, United States of America

Memphis Zoo, Memphis, Tennessee, United States of America

Saint Louis Zoo, Saint Louis, Missouri, United States of America

San Antonio Zoo, San Antonio, Texas, United States of America

San Diego Zoo, San Diego, California, United States of America

ZooTampa at Lowry Park, Tampa, Florida, United States of America

 

 

 Pygmy Hippopotamus, Choeropsis liberiensis

 

Australia

Melbourne Zoo, Melbourne, Victoria, Australia

Belgium

Pairi Daiza, Brugelette, Belgium

Cyprus

Limassol Zoo, Limassol, Cyprus

Czech Republic

Zoologická a botanická zahrada města Plzně, Pilsen, Czech Republic

Zoologická zahrada Jihlava, Jihlava, Czech Republic

Denmark

Aalborg Zoo, Aalborg, Denmark

Givskud Zoo – Zootopia, Givskud, Denmark

France

Le Zoo de La Flèche, La Fléche, France

Parc Zoologique de CERZA, Hermival-les-Vaux, France

Réserve Zoologique de Calviac, Calviac-en-Périgord, France

Zoo du Bassin d'Arcachon, La Teste-de-Buch, France

ZooParc de Beauval, Saint-Aignan, France

Germany

Zoo Leipzig, Leipzig, Germany

Zoologischer Garten Berlin, Berlin, Germany

Zoologischer Garten Halle – Bergzoo, Halle, Germany

Hungary

Nyíregyházi Állatpark, Nyíregyháza, Hungary

Szegedi Vadaspark, Szeged, Hungary

Xantus János Állatkert, Győr, Hungary

Indonesia

Batu Secret Zoo, Batu, Indonesia

Taman Safari Indonesia, Bogor, Indonesia

Netherlands

Koninklijke Burgers' Zoo, Arnhem, the Netherlands

Singapore

Singapore Zoo, Singapore

Spain

Bioparc Fuengirola, Fuengirola, Spain

Bioparc Valéncia, Valencia, Spain

Loro Parque, Puerto de la Cruz, Spain

Switzerland

Zoo Zürich, Zürich, Switzerland

Thailand

Khao Kheow Open Zoo, Si Racha, Chon Buri, Thailand

United Kingdom

South Lakes Safari Zoo, Lindal-in-Furness, United Kingdom

ZSL London Zoo, London, United Kingdom

United States of America

Brookfield Zoo, Brookfield, Illinois, United States of America

Franklin Park Zoo – Zoo New England, Boston, Massachusetts, United States of America

Houston Zoo, Houston, Texas, United States of America

Lincoln Park Zoo, Chicago, Illinois, United States of America

Louisville Zoo, Louisville, Kentucky, United States of America

Montgomery Zoo and Mann Wildlife Learning Museum, Montgomery, Alabama, United States of America

Omaha’s Henry Doorly Zoo and Aquarium, Omaha, Nebraska, United States of America

San Diego Zoo, San Diego, California, United States of America

San Diego Zoo Safari Park, Escondido, California, United States of America

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SUMMARIZE THE EXPERIENCES

 

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The study lists species combinations and mixed exhibits with both species of Hippopotamidae. Altogether 116 mixed exhibits with hippopotamids have been collected from 77 zoological institutions worldwide until May 2022.

The results show that Pygmy Hippopotamus has been listed in 63 and Hippopotamus in 54 mixed exhibits.

In regard to species combinations – but not counting fish species – Pygmy Hippopotamus has been socialized with 107 and Hippopotamus with 101 different species.

 

Hippopotamuses can be very dangerous animals so in former times it was thought that they cannot be combined with other species in captivity (PUSCHMANN 1983). The other basic reason to have not associated them with other taxa was keeping them mostly in small indoors where no space was available for other species. Later on this has changed and huge outdoor enclosures and aviaries as well made it possible to combine them principally with primates and ungulates, but with many species of birds and fish as well. Just as a point of interest GRZIMEK (2000) reported a friendship of an adult female Hippopotamus – which was kept alone in Zoologischer Garten Halle – with a dog which was allowed to crawl into the hippo’s mouth and licked there. Worth mentioning that especially young and playful hippos turn to other species in the absence of playmates and they particularly profit from cohabitations established in mixed exhibits (HAMMER 2002).

There is a known early case of the two hippo species being kept together. A lethal accident has also been registered in reference to that: in 1949 a female Pygmy Hippo was killed by a male Hippopotamus as reported in a former International Studbook (TOBLER 1985).

 

Hippopotamus

 

In nature frustrated Hippopotamuses – particularly younger males – have been known to vent their aggression on other species (KINGDON 1979).

According to the Husbandry Guidelines for the Common Hippopotamus any of the species which can be seen together with hippos in their natural habitat – as mentioned above herons, egrets, storks, spoonbills, geese and ducks – or other African species of birds would exhibit well with them in captivity. Another possibility would be exhibiting arboreal primates which would be safe from the Hippopotamuses up in trees (JONES 2008).

The Adventure Aquarium in Camden has successfully mixed Hippopotamuses (0.2) and Cape Porcupine (2.0) together with assorted species of African Cichlids since 2005. Porcupines were introduced to hippos in the holding area via pen while hippos were on the other side of the area. This procedure was done several times until the Hippopotamuses no longer reacted to their presence in the holding area before introducing them on exhibit. There are strategically placed areas of deadfall branches that the rodents can hide behind or under so hippos cannot reach them. A waterfall with a land area also has been created that the porcupines can walk up but the Hippopotamuses cannot access. The institution has had many species of African Cichlids over the years and there was no introductory period for them. The Hippopotamuses do not bother the fish at all: the success is more about selecting cichlids because they are tolerant of the water quality parameters needed to maintain good exhibit clarity. When the exhibit opened in 2005 it also housed many species of African birds. The species that were most successful housed together with the hippos the following: Cattle Egret, Hamerkop, Abdim’s Stork and Taveta Golden Weaver. All of these species tended to stay well away from the Hippopotamuses. The hippos would occasionally go after any species of birds that would tend to spend too much time on the ground, near the water's edge or fell in the pool. When the staff identified a problem with a specific species they would be moved out of the exhibit. These are the following: Crowned-crane, White-bellied Bustard and Purple Swamphen which species would not move away from the Hippopotamuses on land. Combination was not successful with any species of duck as well: at first ducks would actively avoid the hippos, but over time they would eventually become desensitized to the Hippopotamuses and stop moving away from them in the pool. Eventually all of the birds were moved out in 2013 due to an exhibit redesign process (AZA Ungulate TAGs 2017).

Jerusalem Biblical Zoo kept a single female Hippopotamus in a mixed exhibit with other African species, including Grant’s Zebra, Southern White Rhinoceros, Addax, South African Giraffe, Masai Ostrich and Marabou. The hippo was moved there when she was already old and her mobility was limited so the staff felt confident to put her together with the other species. The hippo died two years ago – at the very respected age of over 59 years old – after living for about 9,5 years in the mixed exhibit without any incidents. Since her death the management has been discussing to introduce young Hippopotamuses into the same exhibit, but this is something that the institution has not done yet, as they feel that with younger individuals there will be a need to first make some major adjustments to the yard to guarantee keeper safety and also that of other species (WERNER 2020, pers. comm.).

The Africa enclosure in Zoo Basel was opened in two stages in 1992 and 1993, where Hippopotamuses, Plains Zebras and Ostriches shared the same habitat. First, a young pair of hippos and a small herd of zebras moved in and one year later the ostriches joined them in the 1750 m² exhibit. For feeding and overnight the hippos and zebras were always separated. Since the opening till 2012, 9 hippos and 37 zebra foals have been born and 240 ostrich chicks have hatched. A problem has arisen when all three species have young at the same time. At the beginning it was soon realised that the originally planned combination was more difficult than expected. The first difficulty was the camouflage behaviour of the young ostriches, since they do not run away when threatened, but lie down on the ground and try to look like a tuft of grass. For the curious zebras the temptation was great to take a closer look at them and if they then started to play with them, this could be dangerous for the chicks. Therefore, until they were big enough they were separated from the zebras. Female zebras with new-born foals – as well as young ostriches – were separated for their first weeks of life, too. Hippopotamuses and zebras lived peacefully together for twelve years. Then, in 2004, the zebra stallion had an accident and a natural barrier was erected with piled up branches, so henceforward direct contact between them was no longer possible. Previously the zebra stallion had been in charge of the enclosure for years. He made it unmistakably clear to the hippo bull where the territorial boundary lay by means of a playful ritual every morning at the edge of the pool. One day the zebra slipped and fell into the water, whereupon the hippo fatally injured the zebra stallion. After that, the hippos no longer left their pond only at night when the zebras were in the pen, but also during the day and thus became a danger to the other species and the zookeepers as well (ZOO BASEL). This was not the only fatal incident in the Africa enclosure caused by hippos. In 2008 a sub-adult Ostrich was bitten to death by a Hippopotamus: the bird slipped on the bank of the water basin and fell in, then the hippo immediately fought off the intruder in its territory and bit.

In smaller enclosures it is important to provide retreats that can only be visited by the subdominant animal species. In Zoologischer Garten Berlin the outdoor enclosures of the Hippopotamuses and Nyalas are adjacent to each other. The antelopes can enter the Hippopotamus enclosure, but can retreat into their own enclosure at any time behind a barrier that is insurmountable for the hippos. The aggressive Nyala buck procures escape into the pool by targeted attacks with violent horn blows into the flanks or the hindquarters of the Hippopotamus (ZSCHEILE & ZSCHEILE 2018). 

In Safaripark Beekse Bergen Hippopotamuses has been held with Western Sitatunga and Nile Lechwe without any problems, additionally there is an old Marabou in the exhibit as well. No problems, but also no cohesion or social behaviour has been reported between the species (VERSTEEGE 2020, pers. comm.).

Parc Le PAL has a very successful mixed exhibit, where Hippopotamuses and Great White Pelicans coexist together perfectly. Beyond a passive cohabitation there are regular interactions between the species: it is not uncommon to see a pelican on the back of a hippo or even the birds are seeking in the mouths of Hippopotamuses. Whether it is on the water or on their island that they all share together, a negative interaction has never been reported. The size of their enclosure – 1,5 hectare and a lake is 1 hectare – probably contributes to the tranquility of the animals (GÉLI 2020, pers. comm.).

In Disney’s Animal Kingdom Theme Park two groups of Hippopotamuses (1.7 or 5.0) have been successfully mixed with Pink-backed Pelican (9.7.2), White-breasted Cormorant (2.2) and with other birds in the past. Hippos are in two separate exhibits and the birds can all move freely from the two enclosures. There are several islands in the deeper water that it is hard for the Hippopotamus to navigate or approach and several logs have also been placed in the exhibit to provide safe places for the birds away from the hippos; this was the key of the success when pelican chicks were hatched as well. The Hippopotamus often become territorial and a few pelicans have been attacked by the hippos when birds get too close to them. In a smaller exhibit another group of Hippopotamus (2.0) has been successfully mixed with White-eyed Duck (1.1) and Tufted Duck (4.2). Ducks were breeding: nest boxes were placed in the exhibit and fixed to the walls so hippos could not move them (AZA Ungulate TAGs 2017).

It is also worth mentioning that several zoos have positive experience keeping their Hippopotamuses in exhibits with large lakes where they coexist together with different species of waterfowl, i. e. Parque de la Naturaleza de Cabárceno, Longleat or Greater Vancouver Zoo just to name a few which combinations have not always been mentioned in the list of mixed-species exhibits.

In 2004, a baby Hippopotamus – named Owen – orphaned by an earthquake was rescued and brought to Haller Park in Mombasa, Kenya. There were no other hippos there, so Owen was associated with Mzee, the park's 130-year-old Aldabra Giant Tortoise.  Shortly they became the subject of media attention after forming an unusual friendship with many interactions between them such as eating, sleeping and playing together. Three years later the tortoise was removed and a female Hippopotamus was introduced. 

In Cheyenne Mountain Zoo there are possible future plans for the Hippopotamuses and Common Warthogs to share the outdoor enclosure in the Water’s Edge: Africa exhibit, but that interaction has not yet been implemented (KOCH 2021, pers. comm.).

 

Pygmy Hippopotamus

 

In the EAZA Ex-situ Programme (EEP) of the Pygmy Hippopotamus various mixed-species exhibits exist with the hippos and different monkey, antelope and bird species. Most holders report no problems, but the Mandrills – especially the males – can be aggressive towards the hippos. Aggression has also occurred between Pygmy Hippos and Blue Cranes, and between Pygmy Hippos and a castrated male Sitatunga. In both cases, the other species were the aggressors. When Pygmy Hippopotamuses are housed with bird species, the institution has to be aware of the fact that hippos killed and fed on several birds, such as ducks, geese or egrets. As birds are often pinioned, this needs to be taken into consideration. In general it is advised not to keep pinioned birds with Pygmy Hippos (HOUWALD et al. 2020).

Zoologischer Garten Halle has lots of experience keeping their Pygmy Hippopotamuses together with several species of New and Old World Monkeys as well. Since 2000 a mixed group of callitrichids – Saddleback Tamarin (0.0.9), Red-chested Mustached Tamarin (1.1) and Goeldi’s Monkey (1.1) – were associated with Pygmy Hippopotamus (1.1) in a 110 m³ indoor enclosure around a giant artificial tree. Later on a group of Mandrill (2.2) were kept together with the hippos only outdoors. The outdoor enclosure was 220 m² with two separated areas and pools for each Pygmy Hippo so the individuals were kept separately. Mandrills had access to the whole outdoor enclosure which was approximately 1000 m³. Both of the species had their own indoor enclosures. Mandrills approached the hippopotamuses to steal food and mutual threats were realized. In general association was not accompanied by major interspecific but by intraspecific problems: initial cohabitation of the two Mandrill pairs was not successful and animals had to be separated again (ZIEGLER 2002). So because of the aggressive male Mandrill the combination with Pygmy Hippopotamus did not work for a longer time (HEUER 2020, pers. comm.).

In the Tropic World Africa exhibit of Brookfield Zoo a Pygmy Hippopotamus (0.1), Talapoin Monkey (various groups), Sykes’s Monkey (3.2), Red-tailed Monkey (1.3), Sooty Mangabey (1.4), Red-capped Mangabey (5.0 or 4.0 or 2.0), Mandrill (1.3), Guereza (3.4) and birds (23 species) were successfully mixed for 16 years. Hippo was always introduced first to new primate species. The institution has only ever maintained one female hippo at a time, but has had three different hippos there from 1982-2012. The addition or removal of primates had no consequence to that of the hippopotamus at the time. The staff had no problems with hippos, but from time to time the monkeys – i.e. Red-capped Mangabeys – harassed the Pygmy Hippo mildly to which she would go back to the pool until the monkey lost interest. In general, all primates and the hippo coexisted without problem. The institution did not stop exhibiting the hippo in this exhibit for lack of success: the management decided to exhibit the species in just one area of the zoo so the Pygmy Hippopotamus has been moved to the Pachyderm House in 2012 (AZA Ungulate TAGs 2017).

The length of time the above-mentioned mixed-species group has been together in Brookfield Zoo: there has been a consistent core group of species – Sooty Mangabey, Mandrill and Guereza – since 1982. The current Sooty Mangabey and Mandrill groups still include some of the original individuals from the 1982 opening of the exhibit. The Sykes’s Monkeys were a consistent part of the exhibit mix for 13 years, from 1982 to 1995. Talapoin Monkeys and Red-tailed Monkeys were also part of the original mixed exhibit, but were removed in 1985. The Red-tailed Monkeys and the Sykes’s Monkeys were not exhibited together due to the potential of hybridization. The original Pygmy Hippopotamus died in 1991 and was replaced. The number and variety of birds has varied since 1982. The method of introduction was to introduce the “smaller more benign” species first – i.e. Talapoin Monkey and Red-tailed Monkey – and work up through the “larger, potentially more aggressive” species – i.e. Sykes’s Monkey, Sooty Mangabey, Mandrill and Guereza. Almost each species had a few days on exhibit alone before any polyspecifics were added to the introduction. In reference to occurrence of birth all primates were regularly bred in the exhibit. Worth mentioning that all primate and bird interactions were negative; it has been reported that some of the birds were eaten or killey by Sooty Mangabeys and Mandrills. In general, the animals are separated at night by species, using different access doors (STRANGE HONEYCUTT 2013).

In Lied Jungle of Omaha’s Henry Doorly Zoo and Aquarium a successful combination of Pygmy Hippopotamus (0.1), Stuhlmann’s Blue Monkey (1.1), Angolan Colobus (2.0) and African Softshell Turtle (1.1) was created in 2011. The species are exhibited together during the day and are separated in night holding due to ensuring they receive the proper diet. The turtles remain on exhibit continuously. The introduction of primates took place in holding area over five days and then they met the hippopotamus and turtles on exhibit: all went very well and was either positive or no interaction has been reported (STRANGE HONEYCUTT 2013).

San Diego Zoo has established a very successful mixed exhibit with Pygmy Hippopotamus (1.1), Wolf's Monkey (2.1.1), Red-flanked Duiker (1.0) and Cape Blue Duiker (2.0) in 2005. The pair of hippos were the first into the exhibit; they were given access round to the bedrooms and exhibit. The duikers and the hippopotamuses were given access to both the exhibit and the bedrooms at night, while the monkeys were kept in the indoor holding at night. According to the introduction method the hippos were the first ones on exhibit. Once they were trained to re-call, the primates were introduced to the holding area. After a few days the monkeys were given access to the exhibit with the Pygmy Hippopotamuses in the barn. Once the monkeys were comfortable they were introduced to the hippos. The Duikers were introduced shortly thereafter with no special accommodations, except for some safety barriers – shade material fixed to the fence – to prevent injuries. The most notable interaction has been reported was that of the juvenile monkey and the Duikers, whom he has become accustomed to riding. This mixed exhibit was considered as a tremendous success for both the animals and the public, as it is one of the most unique and dynamic enclosures in the zoo. In 2012 the duikers were removed from the exhibit; they were managing well, but not thriving due to young Wolf’s Monkeys jumping on their back (STRANGE HONEYCUTT 2013). This interaction can also be frequently observed in reference to the Pygmy Hippopotamuses: the Wolf’s Monkeys are jumping and travelling on the hippos’ back.

San Diego Zoo Safari Park has previously exhibited Pygmy Hippopotamus together with Grant’s Zebra, Grevy’s Zebra, Northern White Rhinoceros, Eastern Black Rhinoceros, East African Sitatunga, East African Eland, Topi, Defassa Waterbuck, Uganda Kob, Red Lechwe, Nile Lechwe, Common Impala, Thomson's Gazelle, Slender-horned Gazelle, Grant's Gazelle, Fringe-eared Oryx, Angolan Roan Antelope, Eastern White-Bearded Wildebeest, Cape Buffalo and Rothschild's Giraffe in a 36 hectare East Africa Exhibit. Over the years the institution has exhibited many of those species together at one time or another and never had any trouble with the hippos, but to tell the truth they mostly stayed on an island in the middle of the pond that was in the exhibit (BLUE 2008, pers. comm.).

Zoo Jihlava tried to mix their Pygmy Hippopotamuses temporarily with several species of waterfowl – i.e. Greylag Goose, Hawaiian Goose and Egyptian Goose – which has generally worked well (VIDUNA 2020, pers. comm.).

In Franklin Park Zoo's Tropical Forest building Pygmy Hippopotamus (1.1), Hartlaub's Duck (1.1) and Rüppell's Vulture (1.1) have been successfully mixed since 2000. The male hippo is still too young to be introduced to the older female so currently each hippopotamus is rotated to the exhibit every other day for display. The vultures have been housed in this exhibit for a long time but over the past two years, these two specimens have been housed outdoors in the summer months. The exhibit also contains Hartlaub's Ducks which were introduced three years ago; these birds mainly inhabit the exhibit pool and so far have had no negative interactions with either the hippos or vultures. An elevated perching and nesting platform is provided for the vultures which is not accessible for the hippos (AZA Ungulate TAGs 2017).

Certain zoos keep Pygmy Hippopotamuses with several fish species – i.e. with Labeo spp. or West African Cichlids. The fish feed on the faeces but do not succeed in clearing the water from debris. Furthermore fish can feed on the skin and wounds of the hippos. The disadvantage of this is that the fish will keep wounds open for longer so careful monitoring is needed (HOUWALD et al. 2020).

 

ACKNOWLEDGEMENTS

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I would like to thank all the persons very much who helped to improve this short summary with providing information and photographs as well, in particular:

 

Jörg BECKMANN Chair of Tapir and Suiform TAG and Vice Director/Biological Director (Tiergarten Nürnberg, Nuremberg, Germany), Andy BLUE former Animal Care Manager, Mammal Department (San Diego Zoo Safari Park, Escondido, California, United States of America), Marc DAMEN former Director General/CEO (Diergaarde Blijdorp, Rotterdam, the Netherlands), Dr. Peter DOLLINGER (Zoo Office Bern, Bern, Switzerland), Monika FIBY Landscape Architect, Zoo Designer and Consultant (ZooLex Zoo Design non-profit Organization, Manager and Chief Editor), Nicolas GÉLI Head of Department of Zoology (Le PAL - Parc d’Attractions et Animalier, Saint-Pourçain-sur-Besbre, France), Katharina HERRMANN Conservation Coordinator (Zoologischer Garten Berlin, Berlin, Germany), Jutta HEUER Scientific Assistant (Zoologischer Garten Halle – Bergzoo, Halle, Germany), Sander HOFMAN General Curator (ZOO Antwerpen – ZOO Planckendael – ZOO Serpentarium, Belgium), Ruben HOLLAND Curator (Zoo Leipzig, Leipzig, Germany), Bengt HOLST former Chair of Tapir and Suiform TAG and Chairman of the Danish Nature Foundation (Copenhagen, Denmark), Brent HUFFMAN Lead Keeper & Zoologist, AZA Ungulates Team (Toronto Zoo, Ontario, Canada), Willeke HUIZINGA Curator of Bush, Desert and Mangrove (Koninklijke Burgers’ Zoo, Arnhem, the Netherlands), Ariel JACKEN Senior Curator (Zoo Leipzig, Leipzig, Germany), Alex KANTOROVICH Euroasian Regional Coordinator at Species360 and Curator (Hai Park, Kiryat Motzkin, Israel), Jenny KOCH Marketing Director (Cheyenne Mountain Zoo, Colorado Springs, Colorado, United States of America), Sarah LAFAUT Curator of Mammals (ZOO Antwerpen – ZOO Planckendael, Belgium), Jonas LIVET Chief Executive & Project Officer (Fox Consulting, Haguenau, France), Zsuzsa PETRÓ Head of Department (Nyíregyházi Állatpark, Nyíregyháza, Hungary), Klaus RUDLOFF Curator Emeritus (Tierpark Berlin, Berlin, Germany), Fabian SCHMIDT Curator (Zoo Basel, Basel, Switzerland), Dr. Alexander SLIWA Curator (Kölner Zoo, Cologne, Germany), Dr. Leszek SOLSKI  Senior Scientific Assistant and Zoo-Historian (ZOO Wrocław, Wrocław, Poland), Beatrice STECK Scientific Assistant and EEP Coordinator (Zoo Basel, Basel, Switzerland), Elodie TRUNET Veterinarian & Curator (Zoo du Bassin d'Arcachon, La Teste de Buch, France), Lars VERSTEEGE Curator (Safaripark Beekse Bergen, Hilvarenbeek, the Netherlands), Richard VIDUNA Head of Zoological Department (Zoologická zahrada Jihlava, Jihlava, Czech Republic), Dr. Noam WERNER General Curator (The Tisch Family Zoological Gardens/Jerusalem Biblical Zoo, Jerusalem, Israel)

 

As well as I would like to thank all the persons very much who helped to improve this document with providing further photographs, their names are listed below:

 

William BEZODIS, Edward BREEZE, Ulrich BRODDE, Kimberly BROWN-AZZARELLO, Stefano CAPOMAGI, Julio Cesar CASTRO GARCIA, Josh CHAMBERLAIN, Davide COLAIANNI, Peter CSANADI, Deane D., Patrick DANNEWITZ, Tom van DEUREN, David EVANS, Zachi EVENOR, Adam FAGEN, Martin FISCH, Joshua FÖRG, David FREELY, Allan GALWAY, Ben GILBERT, Jeremiah GOOD, Nick HADAD, Jerry HENDRICKS, Jiří HLADÍK, Lisa HUBBARD, Kåre JENSEN, Ulli JOERRES, Hector JOZAMI, Asaf KEISAR, D. M. KISTER, Ties KOOISTRA, Wojciech KOPCZYK, Theo LINDERS, Steve MARSHO, Christina MEIER, Nancy MEROLLE, Alexander MEYER, Callum MOORE, Albert de MOS, Antal NAGY, Ruzam NAMOR, Magnus NIEMANN, Eugene, NIKIFOROV, Dustin OLIVER, Keith PARK, Juanjo PO, Eka PRIATNA, Len RADIN, Dan REYNOLDS, Scott RICHARDSON, Judith RICHMANN, David ROBERT, Oren ROZEN, Maarten de RUITER, Alain SECRETAN, Noémi Dalma SOÓS, Robert STREITHORST, Scott THOMAS, Alan TORRES DWYER, Joshua WILKES, Konstantin YORDANOV

 

References:

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HOUWALD, v. F., WENKER, C., FLACKE, G., STECK, B., OSTERBALLE, R., VIDUNA, R. and MATTHEWS, A. 2020. EAZA Best Practice Guidelines for the Pygmy Hippopotamus (Choeropsis liberiensis). First edition. European Association of Zoos and Aquaria, Amsterdam, The Netherlands.

 

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POOLEY, A. C. 1967. Bird/crocodile and bird/hippo commensalism in Zululand. Ostrich 38: 11-12.

 

PUSCHMANN, W. 1983. Wildtiere in Menschenhand; Band Säugetiere. VEB-Dt. Landwirtschaftsverlag Berlin.

 

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SAMISH, M., & REHACEK, J. 1999. Pathogens and predators of ticks and their potential in biological control. Annual Review of Entomology, 44, 159–182.

 

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THOMSON, A. L. 1964. Birds associated with elephants and hippopotamuses. Auk 81: 436.

 

TOBLER, K. 1985. International Studbook for the Pygmy Hippopotamus Choeropsis liberiensis (Morten 1844). 4th edition, Zoological Garden, Basel, Switzerland.

 

WEEKS, P. 1999. Interactions between red-billed oxpeckers, Buphagus erythrorhynchus, and domestic cattle, Bos taurus, in Zimbabwe. Animal Behaviour, 58, 1253–1259.

 

ZIEGLER, T. 2002. Selected Mixed Species Exhibits in Zoological Gardens. Primate Report 64. Selected Mixed Species Exhibits of Primates in German Zoological Gardens. Pp. 7-71.

 

ZSCHEILE, D. & ZSCHEILE, K. 2018. Säugetiere – Zootierhaltung. 6., überarbeitete Auflage.Verlag Europa-Lehrmittel, Nourney, Vollmer GmbH & Co. KG, 42781 Haan-Gruiten

 

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