The pygmy mouse lemur (Microcebus myoxinus) is the smallest primate in the world. Its head and body are less than two and a half inches (six centimeters) long, though its tail is a bit more than twice that length. These endangered nocturnal lemurs live in the dry forests of western Madagascar and rarely leave the forests' trees. Little is known of these rare primates. Mouse lemurs are forest dwellers that live in female-dominated groups of up to 15 animals. They spend most of their time in trees, and can move nimbly from branch to branch and tree to tree. Mouse lemurs sleep aloft during the day and forage at night for insects, fruit, flowers, and other plants. These adaptable primates store fat in their tails and hind legs, burning it when forage is lean. They may store up to 35 percent of their body weight. Female lesser mouse lemurs enter a dormant state during Madagascar's dry season, from April or May to September or October. Females are inactive during this time and may not leave their tree holes. During the same season, however, males are more active. They may be establishing breeding hierarchies for the coming mating season.