A Pygmy Hippo is Born! Hope for This Endangered Species

The Pygmy hippo (Choeropsis liberiensis) is a rare hippopotamus classified as endangered by the IUCN Red List. In February of this year, a new baby of this species was born in Greece, at the Athens’ Attica Zoological Park. This means amazing news for the future of this species, as this baby is male! With a lack of males in the Pygmy hippo population, growth in density has been hard. There are also not a lot of chances with this animal, as female Pygmy hippos only give birth to one calf after 6 or 7 months of gestation. Having the one be a male is truly special.

In honor of this incredible news, we did a profile of this species. So, if you want to know more about Pygmy hippos read below!

Jump links

• Where Does the Pygmy Hippo Live? (Geographic range)
• What Does the Pygmy Hippo Look Like? (Physical Appearance)
• What Does the Pygmy Hippo Eat? (Diet)
• Are Pygmy Hippos Dangerous? (Behavior)
• How Many Pygmy Hippos Are Left? (Conservation status)
• Why are Pygmy Hippos Endangered? (Threats)
• Conservation Efforts to Save the Pygmy Hippo

The last assessment of this species by the International Union of Conservation of Nature (IUCN), was made in 2015. So data about the population density and threats of this species in the wild is outdated. Since 2020, there have been some research papers about Pygmy Hippos, but we couldn’t find a single one dedicated to population density and only one dedicated to threats.

Most of the recent research about this species couldn’t be used to construct this profile, as it’s related to very specific biological processes that do not serve to paint a general picture of the Pygmy Hippo. But rather, appeal to very niche topics within the scientific community.

Taking the previous context into account, as a source, we will be using the information published by the IUCN, as well as three zoos: The San Diego Zoo, the Basel Zoo, and the Marwell Zoo (In that order of hierarchy).

With those disclaimers out of the way, we hope you can get to know the amazing Pygmy Hippo through this profile!

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Where Does the Pygmy Hippo Live?

Geographic range

The Pygmy Hippopotamus (Choeropsis liberiensis) is native to West Africa. Its geographic range includes several countries in the region, primarily Côte d’Ivoire, Guinea, Liberia, and Sierra Leone. While historically, it may have been found in Nigeria, no reliable reports confirm its continued presence there. The Pygmy Hippo’s habitat comprises diverse ecosystems such as forests, savannas, and wetlands, reflecting its adaptability to various environments within its range.

In Côte d’Ivoire, key areas for Pygmy Hippos include Taï National Park, N’Zo Faunal Reserve, Goin Débé Classified Forest, and Azagny National Park. In Guinea, fractured populations are found in reserves like Ziama Biosphere Reserve, Diécké Forest Reserve, and Mont Béro Reserve. Liberia hosts significant populations in Sapo National Park, Grebo National Forest, and other forested areas. In Sierra Leone, Pygmy Hippos are documented in the Gola Forest region, Loma Mountains, and along the Moa River, including Tiwai Island.

Despite being legally protected across its range, the Pygmy Hippo endures severe habitat loss due to deforestation, farming, and human settlement. These factors have led to its retreat into smaller and more isolated forest parcels, making it increasingly vulnerable to extinction.

As you know from the beginning of this post, some zoos have Pygmy Hippos. Here’s a list of those in the USA shown in the book America’s Top 100 Zoos & Aquariums (2020¹):

• Gladys Porter
• Houston
• Lincoln Park
• Louisville
• Montgomery
• Omaha
• Pittsburgh
• San Diego
• Tampa
• Tanganyika
• Wildlife World
• Miami

Also, in 2015, a baby Pygmy Hippo was splashing at the Melbourne Zoo.

What Does the Pygmy Hippo Look Like?

Physical Appearance

The Pygmy Hippo (Choeropsis liberiensis) has distinctive physical traits that differentiate it from its larger relative, the Common Hippopotamus. While it shares a similar appearance, such as a barrel-shaped body and short legs, the Pygmy Hippo showcases some adaptations product of its forest lifestyle.

One of the most notable features of the Pygmy Hippo is its size, significantly smaller than the Common Hippo. This smaller height allows it to navigate dense forest undergrowth with greater agility. Their bodies are more streamlined, with less bulk than their larger cousin, helping them move swiftly through their habitat.

Typically, Pygmy Hippos measure between 75 to 100 centimeters in height at the shoulder, with lengths ranging from 150 to 175 centimeters. Adults usually weigh between 180 to 275 kilograms (although the ones in zoos may exceed these weights due to access to abundant food), which is usually 10 times less than the Common hippo weight.

The skin of the Pygmy Hippo is relatively smooth and hairless, ranging in color from slate gray to brownish-black. This skin protects against abrasions and helps regulate body temperature, something crucial for an animal that spends much of its time in water or muddy environments.

One of the most endearing aspects of the Pygmy Hippo is its expressive face, characterized by large, protruding eyes and mobile ears. These features contribute to their awareness, allowing them to detect potential threats or spot food in their environment.

What Does the Pygmy Hippo Eat?

Diet

Pygmy Hippos (Choeropsis liberiensis) have a varied herbivorous diet, mainly consisting of terrestrial and semi-aquatic vegetation.

Studies have indicated that Pygmy Hippos spend considerable time foraging, with feeding bouts lasting between 5.8 to 6 hours per day. These feeding sessions primarily occur during the night.

In the wild, Pygmy Hippos feed on a diverse selection of vegetation, including ferns, tender roots, grasses, herbs, stems, and leaves of young trees. Fallen fruits are also a welcome addition to their diet when available. Specific dietary preferences may vary depending on multiple factors such as seasonal availability and habitat type.

Interestingly enough, observations suggest that Pygmy Hippos may sometimes venture into agricultural areas, consuming crops such as sweet potato leaves, okra, pepper plants, and cassava. Despite this occasional adventure into cultivated fields, Pygmy Hippos are not considered significant crop pests compared to other herbivores.

Are Pygmy Hippos Dangerous?

Behavior

Pygmy hippos are not typically dangerous to humans, despite their intimidating appearance. Unlike their larger relatives, the common river hippos, pygmy hippos are shy and prefer to avoid confrontation rather than engage in aggressive behavior.

However, while pygmy hippos are generally not aggressive towards humans, it’s essential to remember that they are wild animals so you should treat them with caution and respect. We don’t recommend approaching them in their natural habitat, as they may perceive humans as threats and react defensively. Additionally, keep a good space between you and the pygmy hippos at the zoo; follow the instructions of the establishment when reaching their exhibition.

Something you’d probably want to know is that, when threatened, pygmy hippos may exhibit defensive behaviors. Such as rearing, lunging, scooping water with their mouths, or head shaking. However, their first instinct is typically to flee rather than confront potential threats.

In that same vein, one of the hippos’ most well-known defensive behaviors is the “yawn” display. Despite its name, this behavior is not necessarily a sign of aggression but a warning signal to potential threats. By opening their mouths wide, and displaying their formidable teeth and tusks, hippos can intimidate predators or rivals, deterring them from approaching further.

How Many Pygmy Hippos Are Left?

Conservation status

Pygmy hippos are classified as endangered by the IUCN Red List, with their population estimated to be fewer than 3,000 individuals in their native habitat. This number is based on the IUCN’s latest assessment of this species which was made in 2015. Since it’s been almost 10 years, that information could be outdated. That number most likely changed.

As we said at the beginning of this post, we don’t know for certain how many Pygmy Hippos are left currently, since we couldn’t find more recent publications assessing the Pigmy Hippos population density. However, taking into account that the small and fragmented populations make them particularly vulnerable to extinction, and that back in 2015 the trend was downwards, we expect a decreased population number.

Why are Pygmy Hippos Endangered?

Threats

Pygmy hippos face a lot of threats, primarily stemming from human activities. Among the most significant threats are habitat loss and fragmentation due to deforestation. The conversion of forests for agricultural purposes, logging, and infrastructure development further diminishes their already limited habitats.

Impact of deforestation on Pygmy Hippo populations

As we mentioned previously, Pygmy hippos are native to West Africa. The Upper Guinea Forest (UGF) in West Africa is recognized as a global biodiversity hotspot. However, it has suffered a staggering loss of over 90% of its original area since 1900. Putting endemic species such as the endangered pygmy hippopotamus (Choeropsis liberiensis) at risk.

Despite the critical status of the UGF, the specific causes of deforestation within this region have remained relatively understudied. However, recent research has shown the primary drivers of deforestation, offering valuable insights². Analysis of Sentinel-2 data utilizing the random forest algorithm has revealed three main human processes propelling deforestation between 2000 and 2019 across the pygmy hippopotamus distribution area: shifting agriculture, intensive agriculture, and urban expansion (Erazo-Mera et al., 2024). Alarmingly, the majority of this loss, amounting to 14,900 km2, was attributed to shifting agriculture, highlighting the pervasive impact of this practice on forest ecosystems.

Notably, countries such as Côte d’Ivoire and Liberia bore the brunt of deforestation, accounting for 94% of the net area of forest lost. Far surpassing the levels observed in Sierra Leone and Guinea combined.

Even more concerning is the revelation that forest loss within protected areas, including key reserves like Taï, Sapo, and Gola Rainforest national parks, remains pervasive.

This highlights the urgent need to prioritize conservation efforts that aim to protect forests. To safeguard critical habitats for pygmy hippos and other vulnerable species.

Other threats

Pygmy hippos are not only threatened by deforestation. They also face the threat of pollution of rivers, their primary water sources. This makes the environment unsuitable for their survival.

Additionally, pygmy hippos are victims of hunting and poaching, primarily for their meat. Even more so in areas where logging activities have increased human access to their habitats.

Conservation Efforts to Save the Pygmy Hippo

Pygmy hippos’ conservation efforts span research, protection, management, education, and legislation.

• Regional Pygmy Hippo Conservation Strategy. Developed through collaborative efforts, it outlines objectives and priority actions to address threats and halt the decline of pygmy hippos. Action plans tailored to specific countries, such as Liberia, further articulate objectives and necessary actions for conservation.
• Research and Monitoring. While systematic monitoring schemes are currently lacking, there have been concerted efforts to conduct in-place research to better understand the distribution, trends, life history, ecology, and threats faced by pygmy hippos.
• Habitat Protection. Pygmy hippos benefit from legal protection in all range state countries, with many populations situated within protected areas. Notable protected areas include Taï National Park in Côte d’Ivoire, Sapo National Park and Grebo National Forest in Liberia, and Gola Rainforest National Park in Sierra Leone, among others.
• Awareness. Recent education and awareness programs aim to engage local communities, government agencies, NGOs, academic institutions, and other stakeholders in pygmy hippo conservation efforts.
• International Legislation and Trade Controls. Pygmy hippos are listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), restricting trade in any part of the animal. Additionally, they have protection by national legislation in the countries within their geographic range.
• Captive Breeding. Captive breeding programs contribute to species management, although challenges such as skewed sex ratios and high mortality rates persist. Despite these challenges, captive populations serve as vital reservoirs for genetic diversity and potential reintroduction efforts.

Notes

1. Brown, T., & Richardson, S. (2020). America’s Top 100 Zoos & Aquariums. Independent Zoo Enthusiasts Society. ↩︎
2. Erazo-Mera, E., Younes, N., Horwood, P. F., Paris, D., Paris, M., & Murray, N. (2024). Forest loss during 2000–2019 in pygmy hippopotamus (Choeropsis liberiensis) habitats was driven by shifting agriculture. Environmental Conservation, 51(1), 55–63. doi:10.1017/S0376892923000310 ↩︎