Similar to other species in the weasel family Mustelidae, the sable is long and agile. Its body may grow as many as 20 inches long and its tail adds another several inches to its slender form. The mammal, which only weighs two to four pounds, is a natural climber that prefers to spend most of its time in trees, where it feeds upon eggs, birds, and any other small animals it is able to capture. Generally solitary in habit, sables only couple for breeding purposes and their gestation period is uncommonly long, lasting as many as 300 days. This unusual characteristic is caused by a significant delay in the implantation of the fertilized egg in the uterine wall.