Editing Pygmy hippopotamus (section)

== Description ==
[[File:ZooPygmyHippo.jpg|thumb|Resting at [[Louisville Zoo]]. The skull of a pygmy hippopotamus has less pronounced [[Orbit (anatomy)|orbits]] and [[nostril]]s than a common hippopotamus.]]

Pygmy hippopotamuses share the same general form as a hippopotamus. They have a [[wikt:graviportal|graviportal]] skeleton, with four stubby legs and four toes on each foot, supporting a portly frame. Yet, the pygmy is only half as tall as the hippopotamus and weighs less than 1/4 as much as its larger cousin. Adult pygmy hippos stand about {{cvt|75|–|100|cm|ft}} high at the shoulder, are {{cvt|150|–|175|cm|ft}} in length and weigh {{cvt|180|–|275|kg}}.<ref name="Macdonald, D. 2001">{{Cite book |author = Macdonald, D. |year =2001 |title =The New Encyclopedia of Mammals |publisher =Oxford University Press, Oxford |isbn =978-0198508236}}</ref> Their lifespan in captivity ranges from 30 to 55 years, though it is unlikely that they live this long in the wild.<ref name="The Hippos" /><ref name="National Zoo on pygmy hippos" />

The skin is greenish-black or brown, shading to a creamy gray on the lower body. Their skin is very similar to the common hippo's, with a thin [[Epidermis (skin)|epidermis]] over a [[dermis]] that is several centimeters thick. Pygmy hippos have the same unusual [[secretion]] as common hippos, that gives a pinkish tinge to their bodies, and is sometimes described as "blood sweat" though the secretion is neither [[sweat]] nor [[blood]]. This substance, [[hipposudoric acid]], is believed to have antiseptic and [[sunscreen]]ing properties. The skin of hippos dries out quickly and cracks, which is why both species spend so much time in water.<ref name="The Hippos" />

The skeleton of ''C.&nbsp;liberiensis'' is more [[wikt:gracile|gracile]] than that of the common hippopotamus, meaning their bones are proportionally thinner. The common hippo's spine is parallel with the ground; the pygmy hippo's back slopes forward, a likely [[adaptation]] to pass more easily through dense forest vegetation. Proportionally, the pygmy hippo's legs and neck are longer and its head smaller.<ref name="National Zoo on pygmy hippos" />

[[File:Zwergflusspferd - Pygmy Hippopotamus - Hexaprotodon liberiensis.jpg|thumb|Nuzzling couple at the [[Duisburg Zoo]] in Germany]]
The [[Orbit (anatomy)|orbits]] and [[nostril]]s of a pygmy hippopotamus are much less pronounced, an adaptation from spending less time in deep water (where pronounced orbits and nostrils help the common hippo breathe and see). The feet of pygmy hippos are narrower, but the toes are more spread out and have less webbing, to assist in walking on the forest floor.<ref name="National Zoo on pygmy hippos" />

Despite adaptations to a more [[terrestrial animal|terrestrial]] life than the common hippopotamus, pygmy hippos are still more aquatic than all other terrestrial [[even-toed ungulate]]s. The ears and nostrils of pygmy hippos have strong muscular valves to aid submerging underwater, and the skin physiology is dependent on the availability of water.<ref name="The Hippos" /><ref name="Robinson" />