The mammonetus is found in some medieval encyclopedias. It is some type of monkey, though which kind is not clear. It has a smaller body than an ape. It is brown on the back and white on the belly. It has a long and hairy tail. Because its neck as large as its head, it cannot be leashed by its neck, so it is tied around the belly to prevent its escape. It has a black face very similar to a human face. The hatred between these beasts and the apes is implacable and they are often at war. This beast is born in the East but also lives in the West as if in its own land.