Indris Or Leaping Lemurs
The family Indriidae includes the woolly lemur or avahi, the indri, and two sifakas. These prosimians have only 30 teeth instead of the 36 found in most other lemurs. When on the ground, these primates tend to walk or leap upright.
The indri (Indri indri) is the largest prosimian. Its name comes from a misunderstanding. Early explorers thought the natives were naming the animal when they said, "indri, indri." Instead, they were exclaiming, "There it is" or "Look at that." The indri is quite heavy, weighing more than 13 lb (6 kg) with a head plus body 27 in (69 cm) long. Unlike most prosimians, its tail is insignificant. It is black and cream in color, with an alert, humorous face. The cream color on its rump continues on down the back of its legs. However, some individuals do not have clear color differentiation. Indris live in groups that continually sing (actually closer to a "howl") together, a sound that echoes through their tropical rain forest. They are a protected species, which is fortunate because they do not breed frequently. A female gives birth only once in two or three years.
The sifakas (Propithecus) are soft, fluffy, and fairly large, at least 40 in (102 cm) in length including their long tail. Their whitish color is highlighted by a dark face and crown. Their name is an interpretation of the sound they commonly make. Sifakas often cling to vertical tree trunks and have legs and feet specially adapted for that position. Their legs are longer than their arms, and the big toe is especially long and strong for grasping. The diademed sifaka (P. diadema) of eastern Madagascar is quite rare and has not been studied to any extent; attempts to keep it in captivity have failed. The more common Verreaux's sifaka (P. verreauxi) is a territorial animal that marks its territory using glands located on the throat. The single offspring is carried on the mother's stomach for several months before moving onto her back.
The woolly lemur, or avahi (Avahi laniger), is the smallest member of this family, being only about 12 in (30 cm) long, plus an equally long tail, and weighing about 1.5 lb (0.7 kg). Basically colored gray-brown, it has lighter rings around its eyes. Its major food comes from the mango tree, from which it eats leaves, buds, and bark. Unlike the other indrids, the avahi is nocturnal, and its social groups include only two or three individuals.