Pygmy hippopotamus 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 sunscreening properties. The skin of hippos dries out quickly and cracks, which is why both species spend so much time in water. The skeleton of "C. liberiensis" is more 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
Pygmy marmoset a separate genus for the pygmy marmoset, as "Callithrix" is no longer paraphyletic. There are two subspecies described by Colin Groves of the pygmy marmoset: There are few morphological differences between these subspecies, as they may only differ slightly in color, and they are only separated by geographical barriers, including large rivers in Central and South America. The evolution of this species diverged in terms of body-mass from typical primates, with a high rate of body-mass reduction. This involves large decreases in pre-natal and post-natal growth rates, furthering the thought that pro-genesis played a role in the evolution of this