The Indri is one of the largest lemurs and is native to the lowland and montane forests along the eastern coast of Madagascar, from the Réserve Spéciale d'Anjanaharibe-Sud in the north to the Mangoro River in the south. Herbivorous, they feed mainly on young, tender leaves, but will also eat seeds, fruits, and flowers. Their large greenish eyes and black face are framed by round, fuzzy ears. Their silky fur is mostly black with white patches along the limbs, neck, crown, and lower back. Different populations of the species show wide variations in color, with some northern populations consisting of mostly or entirely black individuals. Their face is bare with pale black skin, and it is sometimes fringed with white fur and they have only a rudimentary tail. They are about 64-72 cm tall and weigh between 6 and 9.5 kg. They maintain an upright posture when climbing or clinging and practice long-term monogamy, seeking a new partner only after the death of a mate. They live in small groups consisting of the mated male and female and their maturing offspring. Like many other species of lemur, indri live in a female dominant society. The dominant female often will displace males to lower branches and poorer feeding grounds, and is typically the one to lead the group during travel. Many groups move 300-700 m daily, with most distance travelled midsummer in search of fruit. They sleep in trees about 10-30 m above ground and typically sleep alone or in pairs. They reach sexual maturity between the ages of 7 and 9 and females bear offspring every two to three years, with a gestation period around 120-150 days. The mother is the primary caregiver, though the father assists, remaining with his mate and offspring, despite the infant clinging to their mother's belly until they are four or five months old, at which time they move onto her back. The indri begins to demonstrate independence at eight months. They are the only mammal other than humans so far discovered which can use rhythm. They make loud, distinctive songs, which can last from 45 seconds to more than 3 minutes. Song duration and structure varies among and even within groups, but most songs have a three-phase pattern. Usually, a roaring sequence lasting for several seconds will precede the more characteristic vocalizations. All members of the group except the very young participate in this roar, but the song proper is dominated by the adult pair. Different indri groups typically sing sequentially, responding to one another. As well as solidifying contacts between groups, the songs may communicate territorial defense and boundaries, environmental conditions, reproductive potential of the group members, and warning signals. Countless variations are given on the legend of the indri's origins, but they all treat them as sacred animals who are not to be harmed. Despite the origin myths and traditional taboos (fady), however, in practice where western influence is felt and economic times are tough, they are hunted and their habitat destroyed due to slash and burn agriculture, fuelwood gathering, and logging. They are a critically endangered species. While population estimates are uncertain (1000 to 10000 individuals), the population appears to be rapidly shrinking and may diminish by 80% over the next three generations.