Arboreal locomotion small branches, as they may wrap too far around and prick the animal's own paw. Adhesion is an alternative to claws, which works best on smooth surfaces. Wet adhesion is common in tree frogs and arboreal salamanders, and functions either by suction or by capillary adhesion. Dry adhesion is best typified by the specialized toes of geckos, which use van der Waals forces to adhere to many substrates, even glass. Frictional gripping is used by primates, relying upon hairless fingertips. Squeezing the branch between the fingertips generates a frictional force that holds the animal's hand to the branch. However, this
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