The intelligence that gradually developed among the basal non-avian coelurosaurs enabled them to adapt to all kinds of harsh conditions. The large brain of the mountain leaper coordinates its movements, and enables it to make swift judgments as it springs and leaps between the spires and crags of the mountain peaks, hunting the small birds and small mountain placental mammals on which it feeds. It has developed a high degree of endothermy (warm-bloodedness) to help it to cope with the icy climates, and the thick shiny feathers are indicative of this, providing the insulation that keeps the animal's body at a constant temperature. The head and body reach a length of about 1 meter (3 feet), but the flowing hair-like feathers, the long legs and long balancing tail with its spectacular plume make it look much larger. Mountain leapers live in small packs, with the males undertaking all the hunting, and protection of the females and the young.