Tree squirrel Tree squirrel Tree squirrels are the members of the squirrel family (Sciuridae) commonly just referred to as "squirrels". They include over a hundred arboreal species native to all continents except Antarctica and Oceania. They do not form a single natural, or monophyletic group; they are related to others in the squirrel family, including ground squirrels, flying squirrels, marmots, and chipmunks. The defining characteristic used to determine which species of Sciuridae are tree squirrels is dependent on their habitat rather than their physiology. Tree squirrels live mostly among trees, as opposed to those that live in burrows in the ground or
Asháninka arboreal chinchilla rat and lips, large claws, and a line of white fur running down its head. It is in length, with a tail of . It weighs . Ashaninka arboreal chinchilla rats live in dwarf forest and are hunted by long-tailed weasels. When described, it was placed in the family Abrocomidae, but was considered different enough from existing species for the creation of the genus "Cuscomys". Since then, the Machu Picchu arboreal chinchilla rat ("Cuscomys oblativus"), a species of chinchilla rats originally placed in the genus "Abrocoma", has been shown to be a member of "Cuscomys". Although it was considered extinct by