The trees are alive with myriads of tiny insectivorous arbrosaurs, each one differing from the next by the different colours of the feathery pelt, by different display tufts on the head and tail, and by slight differences in the shape and size of the head. The arrangement of the skull and jaws depends upon the diet. Feeding both in the trees and on the ground, the tiny arbrosaurs have short, thick jaws to crunch up beetles, or long thin jaws to dig for buried larvae and worms. All the arbrosaurs have the same light build, long, springing legs and thin toes. The body is small and balanced for running and jumping by the long, stiff tail.
The footle is a typical narrow-jawed arbrosaur. It is about 50 centimeters (1 1/2 feet) long but most of this is made up of the long tufted tail. The body weighs only a few grams. It is a very agile little creature, scampering along boughs and leaping from branch to branch with ease.