---
title: "What the sources say about the Pygmy Hippopotamus | AnimalTracks.wiki"
description: "61 claims from the Pygmy Hippopotamus profile, each beside the words of the source that backs it."
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# What the sources say about the Pygmy Hippopotamus (*Choeropsis liberiensis*)

> 61 claims from the Pygmy Hippopotamus profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Pygmy Hippopotamus](https://animaltracks.wiki/animals/pygmy-hippo/)

## Pygmy Hippopotamus. San Diego Zoo Wildlife Alliance.

https://animals.sandiegozoo.org/animals/pygmy-hippopotamus

| The page says | The source says |
| :--- | :--- |
| pink blood-sweat sunscreen | its skin oozes out a pink fluid that looks like beads of sweat (note: same paragraph: 'This fluid, called blood sweat, helps to protect a pygmy hippo's sensitive skin from sunburn.') |
| found on the forest floor or in swamps | Pygmy hippos search for food on the forest floor or in swamps |
| Pygmy hippos measure 4.9 to 5.7 feet long and stand 30 to 39 inches tall, weighing 350 to 600 pounds | Length: 4.9 to 5.7 feet (1.5 to 1.75 meters) (note: same page also gives Height: 30 to 39 inches (75 to 100 centimeters) tall, and Weight: 350 to 600 pounds (160 to 270 kilograms), each under its own SIZE heading) |
| a common river hippo weighs about 10 times as much | A common or river hippo weighs about 10 times as much as a pygmy hippo. |
| San Diego Zoo gives females an average lifespan of 31 years, without saying whether in the wild or in zoos, and lists the male lifespan as unknown | 31 years on average for females, uknown for males (note: the page's LIFE SPAN line gives no wild or captive scope, so the sentence attributes it and says so) |
| it usually lives alone, though it is sometimes found in small family groups | Pygmy hippopotamuses are usually solitary but can sometimes be found in small family groups. |
| It is found only in the interior forests of West Africa, mainly in Liberia, with small numbers in neighboring Sierra Leone, Guinea and Ivory Coast | found only in the interior forests in parts of West Africa, mainly confined to Liberia, with small numbers in the neighboring countries of Sierra Leone, Guinea, and the Ivory Coast |
| San Diego Zoo puts the wild population at possibly fewer than 2,500 | possibly less than 2,500 individuals remaining in their native habitat |
| Its forests are being cut down or burned, its rivers polluted, and in logged areas people hunt it for meat | The forests that shelter them are being cut down or burned away, and the rivers where they swim are now polluted by people. In logged areas, people hunt them for their meat. |
| They rest hidden in swamps, wallows or rivers through the heat of the day | resting while hidden in swamps, wallows, or rivers during the heat of the day until dark |
| leave the water to feed on land for a few hours in the cool of the night | when they leave the water to feed on land for a few hours in the cool of the night |
| they can stand on their hind legs to reach food higher up in trees | can stand on their hind legs to reach food higher up in trees if they need to |
| Leopards seem to be the only natural predator able to successfully attack them | Leopards seem to be the only natural predator able to successfully attack pygmy hippos. |
| Pygmy hippos are shy and would rather flee than fight | pygmy hippos are shy and would prefer to flee rather than stay and fight |
| thin | The top layer of a pygmy hippo's greenish-black skin is smooth and thin |
| Newborn calves weigh 7.5 to 14 pounds | Weight at birth: 7.5 to 14 pounds (3.4 to 6.4 kilograms) |
| reach maturity at 4 to 5 years | Age of maturity: 4 to 5 years |
| A pygmy hippo weighs 350 to 600 pounds | Weight: 350 to 600 pounds (160 to 270 kilograms) |
| The pygmy is usually solitary | Pygmy hippopotamuses are usually solitary |
| its head is rounder and narrower, with eyes that are not on top of it | their heads are rounder and narrower, their necks are proportionally longer, and their eyes are not on top of their heads |
| San Diego Zoo says there are possibly fewer than 2,500 left in the wild, in only four West African countries | Known to live in only four countries in West Africa , pygmy hippos are now classified as Endangered, with possibly less than 2,500 individuals remaining in their native habitat |
| Their forests are being cut down or burned, their rivers polluted, and in logged areas people hunt them for meat | The forests that shelter them are being cut down or burned away, and the rivers where they swim are now polluted by people. In logged areas, people hunt them for their meat. |
| The species is classified as Endangered. | pygmy hippos are now classified as Endangered |
| weightKg: 215 | Weight: 350 to 600 pounds (160 to 270 kilograms) (note: 215 is the midpoint of the San Diego Zoo range; the whole range sits in the engine's Heavy class (100 to 999 kg), which the name guess missed because 'pygmy' blocks the hippo rule.) |

## Hexaprotodon liberiensis (pygmy hippopotamus). Animal Diversity Web, University of Michigan.

https://animaldiversity.org/accounts/Hexaprotodon_liberiensis/

| The page says | The source says |
| :--- | :--- |
| never far from swamps, streams or rivers | Hexaprotodon liberiensis is only found in low-lying, forested areas, never far from a source of water. Pygmy hippopotamuses use swamps, streams, and rivers as refuges |
| Broad-leaved plants, grasses, semi-aquatic plants, sedges, ferns and fallen fruit | herbs, broad-leaved plants, grasses, semi-aquatic plants, herbaceous shoots, forbs, sedges, ferns, and fallen fruit |
| A glossy "blood sweat" from glands in its skin that protects its thin, sensitive skin from the sun | Large glands in the dermis produce a glossy, brownish-red secretion that is referred to as “blood sweat”. These secretions protect the sensitive skin from sun. (note: 'thin': SDZ 'The top layer of a pygmy hippo's greenish-black skin is smooth and thin') |
| with more of it seen during hard exertion | the production of the blood sweat has been observed to increase when intense physical exertion such as running or mating takes place |
| Unlike its social cousin | Unlike their social cousins, Hexaprotodon liberiensis is solitary. |
| Pygmy hippos avoid open ground completely and do most of their travelling along worn, tunnel-like paths through dense vegetation | Open areas are completely avoided and most travel is limited to worn-down, tunnel-like paths through dense vegetation on land. |
| Their plant diet includes broad-leaved plants, grasses, semi-aquatic plants, sedges, ferns and fallen fruit | herbs, broad-leaved plants, grasses, semi-aquatic plants, herbaceous shoots, forbs, sedges, ferns, and fallen fruit |
| when startled, they flee a short distance into vegetation and hide | When startled, pygmy hippos flee a short distance into vegetation, where they hide. |
| Blood sweat comes from large glands in the dermis | Large glands in the dermis produce a glossy, brownish-red secretion that is referred to as “blood sweat”. (note: the dermis gloss is a general definition) |
| This glossy, brownish-red secretion protects the pygmy hippo's thin, sensitive skin from the sun | These secretions protect the sensitive skin from sun. (note: 'thin': SDZ 'The top layer of a pygmy hippo's greenish-black skin is smooth and thin') |
| more of it has been seen during hard exertion such as running or mating | the production of the blood sweat has been observed to increase when intense physical exertion such as running or mating takes place |
| It may have evolved to replace sweat. | It may be an adaptive replacement of sweat (note: paraphrase: 'adaptive replacement' as 'evolved to replace') |
| It is a glossy, brownish-red secretion made by large glands in the dermis | Large glands in the dermis produce a glossy, brownish-red secretion that is referred to as “blood sweat”. |
| It protects the pygmy hippo's sensitive skin from the sun | These secretions protect the sensitive skin from sun. |
| more of it has been seen during hard exertion such as running or mating | has been observed to increase when intense physical exertion such as running or mating takes place |

## Flacke & Decher (2019). Choeropsis liberiensis (Artiodactyla: Hippopotamidae). Mammalian Species.

https://doi.org/10.1093/mspecies/sez017

| The page says | The source says |
| :--- | :--- |
| Dwarf solitary forest hippo of the Upper Guinean swamps | A solitary, forest-dwelling ungulate endemic to the Upper Guinean forest ecosystem in West Africa (note: 'Dwarf' is the common name's 'pygmy'; swamps: ADW 'Pygmy hippopotamuses use swamps, streams, and rivers as refuges') |
| Low-lying forests of West Africa's Upper Guinean forest zone | endemic to the Upper Guinean forest ecosystem in West Africa (note: ADW: 'only found in low-lying, forested areas, never far from a source of water') |
| is the smaller of the two living hippo species | The smaller of the two extant hippopotamids |
| the only living species in its own genus | is the only extant species in the genus Choeropsis (note: the genus gloss is a general definition) |

## Fisher, Scott & Naples (2007). Forelimb myology of the pygmy hippopotamus (Choeropsis liberiensis). The Anatomical Record.

https://doi.org/10.1002/ar.20531

| The page says | The source says |
| :--- | :--- |
| Hippos walk along river and lake bottoms rather than swim, a 2007 study of pygmy hippo front legs points out | these adaptations differ functionally from most aquatic mammals as hippos walk along river or lake bottoms, rather than swim (note: 2007 and 'front legs' (forelimb) are the paper's year and title) |
| Dissecting two animals from a Washington, D.C. zoo | Two specimens from the National Zoological Park in Washington, D.C. were dissected |
| its authors found broad anchor points for the chest muscles and a long tendon to bend each toe, because every toe carries weight | mm. pectoralis superficialis and profundus demonstrate broad sites of origin, while the long flexor tendons serve each of the digits, reflecting the fact that all toes are weight-bearing (note: pectoralis = chest muscles, site of origin = anchor point, flexor = bending) |
| Together these give a strong system for pushing the body forward through water | Several findings highlight a robust mechanism for propelling the trunk forward through the water. |
| walks along the bottom rather than swimming | these adaptations differ functionally from most aquatic mammals as hippos walk along river or lake bottoms, rather than swim |
| with every toe bearing weight | the long flexor tendons serve each of the digits, reflecting the fact that all toes are weight-bearing |

## Saragusty et al. (2012). Male pygmy hippopotamus influence offspring sex ratio. Nature Communications.

https://doi.org/10.1038/ncomms1700

| The page says | The source says |
| :--- | :--- |
| The 2008 pygmy hippo studbook lists 1,089 captive births between 1919 and 2008 | The 2008 pygmy hippopotamus studbook lists 1,089 captive births between 1919 and 2008. (note: the studbook gloss is a general definition) |
| of the 1,057 with a known sex, about 42% were male | The sex ratio of all captive births of known sex was 0.4248 (449 males out of 1057 births) (note: 42% is 0.4248 rounded) |
| A 2012 study of ten captive males | These ten males constitute 10% of the entire world captive adult male population in this species. (note: 2012 is the paper's year) |
| every male made more sperm carrying an X chromosome, which produces daughters, than sperm carrying a Y | The sex ratio of the sampled sperm was skewed towards an excess of X-chromosome-bearing spermatozoa in all individuals (note: 'which produces daughters' is general mammal biology; the paper: 'result in the production of an excess of female offspring') |
| The researchers think females most probably add a similar tilt, though they could not rule out the males alone | male and female interests most probably converged and that both male (0.4337) and female (0.4159) biases in sex allocation result in the production of an excess of female offspring (note: same paragraph: 'the possibility that the female is neutral to the outcome and the bias is by the males only cannot be ruled out') |
| and of the 1,057 with a known sex, about 42% were male | The sex ratio of all captive births of known sex was 0.4248 (449 males out of 1057 births) (note: 42% is 0.4248 rounded) |
| 2012 study of ten captive males found that every one made more sperm carrying an X chromosome | The sex ratio of the sampled sperm was skewed towards an excess of X-chromosome-bearing spermatozoa in all individuals (note: 2012 is the paper's year; N=10 per Methods: 'These ten males constitute 10% of the entire world captive adult male population') |
| dangerLevel: Medium | male–male or male–female encounters often take an aggressive course and fighting may lead to severe injuries and death (note: Capability, not frequency: the animal can do serious harm to its own kind, but SDZ says 'pygmy hippos are shy and would prefer to flee rather than stay and fight' and ADW records 'no known adverse effects' on humans, so not High.) |

## Houa et al. (2022). Animal reactivity to camera traps and its effects on abundance estimate using distance sampling in the Taï National Park, Côte d'Ivoire. PeerJ.

https://doi.org/10.7717/peerj.13510

| The page says | The source says |
| :--- | :--- |
| In Ivory Coast's Taï National Park | Animal reactivity to camera traps and its effects on abundance estimate using distance sampling in the Taï National Park, Côte d'Ivoire (note: the paper's title; the camera-trap gloss is a general definition) |
| estimated pygmy hippos available for the cameras to detect 49% of each 24 hours | the determined availability was 49% over a 24-hour period |
| the gaps came from resting in the shallows and rivers | It was not available for detection at all times because of resting in the shallows and rivers. |

## Ransom, Robinson & Collen (2015). Choeropsis liberiensis. The IUCN Red List of Threatened Species 2015: e.T10032A18567171.

https://doi.org/10.2305/iucn.uk.2015-2.rlts.t10032a18567171.en

| The page says | The source says |
| :--- | :--- |
| rates it Endangered | IUCN Red List category: Endangered (EN). (note: the Red List gloss is a general definition) |