Golden
lion tamarins (GLTs) are small (500-600 grams) monkeys native
to Brazil. They live in the heavily populated coastal region
of Brazil, where less than 2 percent of the forest remains.
They are endangered because their habitat has been fragmented into small, unconnected areas, each area only capable of supporting a small number of groups. Without intervention inbreeding would soon result in the local extinction of many of these small populations of tamarins, and eventually of the entire species.
About 1,000 GLTs live in the wild, most in or near the Reserva Biologica de Poço das Antas in the state of Rio de Janeiro. About 500 live in zoos worldwide.
Habitat
In
Poço ("POH-so") das Antas, golden lion tamarins
prefer swamp forest. Swamp forest contains many vines and
bromeliads, and has a high density of fruit and animal foods.
Because all of this land has been logged in the past, we don't
know what kind of habitat GLTs originally preferred. Presumably
the preferred a humid, closed canopy forest with many vines,
bromeliads and other epiphytes. The closed canopy and tangles
of vines provide easy arboreal pathways and protection from
aerial predators. The bromeliads host many insects and small
vertebrates that are important tamarin foods. They are also
an important water source.
In the wild, GLTs sleep in tree holes. Tree holes are important for heat conservation and protection from nocturnal predators.
Diet
Golden
lion tamarins are omnivorous, feeding on fruits, insects,
and small vertebrates. Any smaller animal is possible food.
GLTs actively search crevices, bark, bromeliads, and other
hiding places for their prey. They use their long, slender
fingers and hands to probe into these areas, a behavior called
"micromanipulation".
In
zoos, GLTs are fed fruit (bananas, apples, and oranges), canned
marmoset diet, mealworms, and crickets. They supplement this
with cockroaches, mice, and other uninvited guests that aren't
quick enough to escape.
Predators
Hawks
and other raptors, cats, and large snakes are the main predators
of GLTs. Data on predation are difficult to obtain. The tamarins
give alarm calls in response to strange and/or threatening
stimuli. They have a particular alarm call for large birds
overhead. When that call is made the animals head for the
trunks of the trees or sometimes just let themselves fall
to the ground. The alarm call and the response seem to be
genetically "hard-wired". Zoo born animals that
have always lived inside make the call and respond appropriately
when birds fly over.
Social Behavior
In
zoos GLT are kept in family groups. In the wild, groups are
small (2-9 animals) and usually consist of one breeding adult
of each sex and younger animals. The group members could be
related (i.e. a family group) but transfer of animals between
groups has been seen and may be quite common.
Tamarin groups actively defend a territory against other GLTs. Territories average 40 hectares (about 100 acres). The defense of a territory is accomplished through vocalizations and scent marking during ritualized group encounters. Actual fighting does not occur.
Occasionally more than one adult male (or, less commonly, more than one female) will breed in a group. Whether this represents a transitional situation, an alternate reproductive strategy based on cooperative rearing of infants, or just variation in tolerance between adults is unknown.
In captivity aggression occurs between animals of the same sex, especially between adult females. Mothers have been known to attack their older daughters, resulting in the death of one or more animals if they are not separated. Males appear to be more tolerant of each other, but will fight on occasion.
Births are usually twins. Infant care is cooperative. All members of the group will carry an infant, with the adult male commonly doing the largest share. The mother only takes the babies to nurse them. Since a set of twins might weigh as much as 15 to 20 percent of the mother's weight, she can use the help.
Young animals benefit from their experience with younger siblings. Males and females with previous care-giving experience as youngsters are much more likely to successfully raise their infants from the start. Pairs without prior infant experience often lose several sets of infants before they become competent parents.
Food is shared on occasion. Sharing is both passive (i.e. tolerated stealing) and active, with the food actually offered to another animal. Usually the food goes from older to younger animals. Often young animals will make a rasping noise (known as an infant rasp) as they try to take food from another animal.
GLTs retire at dusk and sleep until after sunrise. The adults are the first out of the holes in the morning and the last to enter at night. In the zoo they sleep in nestboxes. If a nestbox is available GLTs will always sleep in one.
Other GLT Facts
Gestation Length: 126 - 130 days
Time to weaning: 90 days
Age at sexual maturity: 18 months
Life expectancy (in captivity): about 8 years for animals
that survive past the infant stage - 40 percent of infants die before
1 year.
Longevity record - 28 years (and counting)
All photos on this page were taken by James M. Dietz, UMD and used with permission.
