BLACK LION TAMARIN
Geographic Distribution and Habitat
The black lion tamarin (Leontopithecus chrysopygus), also known as the golden-rumped lion tamarin, is endemic to a small area of southern Brazil. Living exclusively in the Atlantic Forest in the Brazilian state of São Paulo, its range has been restricted in recent years due to human alteration of its habitat. Black lion tamarins are limited to just 15 isolated forest patches covering just 190 square miles (490 square km). Unlike its close relatives, black lion tamarins are restricted to inland areas and do not live along the coast. They usually live in semi deciduous forests, although they may also be found in swamp forest and macega, forests made up of small bushy trees.
There are four species of lion tamarins, which share the genus Leontopithecus: the golden lion tamarin (L. rosalia), the golden-headed lion tamarin (L. chrysomelas), the Superagui lion tamarin (L. caissara), and of course the black lion tamarin. Molecular evidence suggests that golden lion tamarins are the closest relatives of black lion tamarins.
Size, Weight, and Lifespan
Black lion tamarins are about 8–13 inches (20–33 cm) long, with their tail adding another 12–16 inches (31–40 cm). They weigh between 11 and 25 oz (300–700 g). They live to about 10 years of age in the wild, but have been known to live to the age of 28 in captivity.
Black lion tamarins follow the color scheme of their close relatives: black and orange. While at first glance black lion tamarins may appear to be as entirely black as their name suggests, their rumps, their thighs, and base of their tails are varying degrees of rusty orange. This is much more apparent in baby black lion tamarins who appear to be wearing orange shorts! Their hair is silky and dense, although they are bald on their face, hands, and feet, which are dark gray or black. Their back legs are slightly longer than their arms. Their tail is not prehensile nor are their thumbs opposable. All their digits, with the exception of their big toes, have a long, scythe-like claw that helps them to grip branches. The nails of their big toes are flat.
Black lion tamarins are omnivorous, eating mostly fruit and insects. They opportunistically feed on lizards, small birds, other small vertebrates, and eggs when they get the chance.
Behavior and Lifestyle
Black lion tamarins are arboreal (tree-dwelling), spending nearly their entire lives 10–40 feet (3–12 m) above ground and rarely venturing to the forest floor. They are diurnal and active for about 9–12 hours per day, emerging from their sleeping sites just after sunrise and finding a new one in the evening.
Lion tamarins are notoriously difficult to study because they have a knack for easily disappearing from the view of researchers. This makes radio telemetry (a common tracking tool used in wildlife biology) extremely important for researchers of these unique primates.
Black lion tamarins have been formally declared the symbol of natural heritage and wildlife conservation by the Brazilian state of São Paulo, where they are endemic.
Black lion tamarins are highly social and live in small family groups, typically composed of a mated pair and two or three of their offspring. Black lion tamarins are territorial, with the primary male and female of each family group defending their territory, which is typically 75–125 acres (30–50 ha) in size—although as available habitat decreases, territories are becoming smaller and more overlapped. Sometimes, family groups come together in gatherings where young black lion tamarins find mates to start their own groups. During these large gatherings, the dominant, mature males and females typically keep to themselves while the younger individuals find mates.
Lion tamarins are known to use a number of communication methods. Vocalizations are often used. Long calls are made between mated pairs, while trills and clucks are used when they are foraging alone. Scent marking and body language are other likely communication methods used by black lion tamarins.
Black lion tamarins are believed to be mostly monogamous, although polyandry, the mating of one female to multiple males, has also been observed. Polyandry is believed to be used by females to make multiple males believe that the offspring is his, and thus help in raising it.
Tamarins are one of the few primate groups that usually give birth to twins, although singlets, triplets, and even quadruplets have been reported. Their gestation length is about 130 days. They usually give birth during the rainy season, September through March.
Baby black lion tamarins are born with their eyes open and all their hair, although they are still heavily reliant on their parents for care. Their mother does the bulk of childrearing during the first two to three weeks of her baby’s life. After this point, the father carries the baby the majority of the time and brings him back to the mother to nurse every few hours. They are weaned by about two or three months, but stay with their group until reaching sexual maturity at 1.5 to 2 years of age.
Black lion tamarins are predated on by animals such as cats, birds of prey, and snakes. Living in a group helps to protect them, as all members of the group look out for predators and warn others. Black lion tamarins likely serve as seed dispersers due to the fruit that they eat.
The International Union for Conservation of Nature lists black lion tamarins as Endangered (IUCN, 2020), appearing on the IUCN Red List of Threatened Species. This designation is due to a predicted population loss of more than 50% over the next twenty years, or about three generations. There are only an estimated 1,600 remaining mature black lion tamarins alive today, living in just 15 forest patches. Only one of these subpopulations, the 1,200 black lion tamarins in Morro do Diabo State Park, is considered “viable” by scientists, meaning that it has enough individuals—at least 750, according to researchers—to retain enough genetic diversity for the species. Populations that are too small do not have the genetic diversity to survive in the long-term. The other 14 subpopulations all have fewer than 80 animals and live on less than 6,000 acres (2,400 ha). These subpopulations are not expected to survive in the long term, and may even be extirpated—or locally extinct—by 2050.
Further habitat loss of 10–15% by 2040 is expected, and the already small black lion tamarin subpopulations will become even more fragile. Of particular concern are “stochastic events.” These are unpredictable events, such as extreme weather or disease outbreaks, that can significantly harm populations. The smaller and more disjointed a population is, the more harm these stochastic events can do. For example, an outbreak of yellow fever beginning in 2018 resulted in the deaths of one-third of wild golden lion tamarins, the closest living relatives of black lion tamarins. Low genetic diversity can play a role in a species’ susceptibility to these stochastic events as well. If a species has low genetic diversity, all or most of its individuals may be vulnerable to a particular disease, like “putting all your eggs in one basket,” as the saying goes. A more genetically diverse population will have more individuals that are resistant to the disease, so they are more resilient to these events.
Compounding all these issues is climate change. Models show that climate change will shift suitable black lion tamarin habitat southwards in the coming decades and result in an overall reduction in suitable black lion tamarin habitat of 28%. As the climate changes and suitable habitat shifts southwards, black lion tamarins will need to follow that shift and move south. But because black lion tamarins live in “islands” of forest, there is presently no viable way for them to make that move. Unless a network of habitat corridors is created, the black lion tamarins will have nowhere to go and will be left in unsuitable habitat as the climate changes. This will spell disaster for the species unless significant conservation efforts are undertaken. One model shows that black lion tamarins will be exposed to these climate impacts within 60 years.
Black lion tamarins are listed in Appendix I of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival. Current conservation efforts mainly center around managing the species’ genetic diversity. Managers relocate the animals between populations, and there is a captive breeding effort hoping to introduce genetic diversity to otherwise isolated populations. There are also efforts to restore corridors of habitat between the subpopulations, to allow the animals to move between them. Economic development programs are also being implemented, which will provide long-term employment to locals living in the black lion tamarin range, providing jobs in fields such as seedling production and ecological restoration. These programs hope to curb unsustainable deforestation while protecting people’s livelihoods. Black lion tamarins live in a number of protected areas, including Morro do Diabo State Park and the Angatuba State Ecological Station, although their value as black lion tamarin habitat will likely decrease as climate change progresses.
- Meyer, A.L., Pie, M.R. and Passos, F.C. (2014), Assessing the exposure of lion tamarins (Leontopithecus spp.) to future climate change. Am. J. Primatol., 76: 551-562. https://doi.org/10.1002/ajp.22247
Written by K. Clare Quinlan, November 2022