scans for insects from above, usually four meters above the forest floor. The black lion tamarin eats the gum and fruit of trees, climbing up to ten meters to reach them and as these are easily found, the tamarin spends 12.8% of its day obtaining them, rather than the 41.2% of the day spent foraging for insects in the high trees. Reproduction Black lion tamarins mate and have offspring during the spring, summer, and fall months (August to March in Brazil). Females usually have one litter per year, though 20% females produce two litters per year. The mean litter size is two infants. Most mammals produce a 50:50 ratio of males to females. The black lion tamarin population almost always produce a 60:40 male to female ratio. Most infants deaths occur within the first two weeks of birth, with newborns of first-time mothers having the lowest survival rates. The number of tamarins that survive to adulthood in the wild is 10% higher than those in captivity. Food sharing During the first few months after birth, the infant is unable to obtain food on its own. For this reason, the infant rides on the parent's back and receives food from the parents. It drinks milk in the 4 to 5 weeks after birth; after that, the parents and other group-members share food with the infant. Sharing involves both offers from the parents and begging by the infant. Usually, until the age of approximately 15 weeks, the infant will receive the majority of its food (especially insects) from others. The number of offers from group-members peaks at week 7; after week 15, sharing slowly declines, stopping by week 26. Communication Within Leontopithecus, the black lion tamarin is the largest in size and has the lowest-pitched calls, using longer notes than other species. The black lion tamarin use calls to defend territory, maintain cohesion within the group, attract a mate, and contact individuals who might be lost. Most calls can be recorded in the morning, and can be attributed to the reunion of mated pairs. Mated pairs are mostly monogamous but polyandry has been observed in some populations. Conservation The black lion tamarin is rated endangered by the IUCN Red List due to its declining population trend. The main threat against it is the destruction of its habitat through deforestation, though it is also threatened by being hunted in unprotected forests, such as