Chadoo

The Chadoo are small, tree-dwelling creatures native to the Hork-Bajir homeworld.

Biology
A chadoo has four short, stubby legs and two enlongated arms that end in claws which are connected by skin flaps and is covered in feathers. Very quick and agile, it is capable of moving, jumping, and using its skin flaps to glide from tree to tree. It primarily feasts on tree sap. The chadoo may be an evolutionary cousin to the Arn.

Source

 * Animorphs: The Hork-Bajir Chronicles
 * Animorphs: The Prophecy