GOLDEN LION TAMARIN
Geographic Distribution and Habitat
The Atlantic Forest of southeastern Brazil is home to the golden lion tamarin (Leontopithecus rosalia), considered a flagship species. Once found throughout the lowland coastal regions of the states of Rio de Janeiro and Espirito Santo, centuries of deforestation and encroaching urban development have wiped out 98 percent of its original habitat—nearly causing the species’ extinction. Fortunately, golden lion tamarins have shown resilience, adapting to degraded and secondary forests.
Today, this diminutive New World monkey is relegated to four small fragments of hilltop and swamp forests, residing at less than 984 ft (300 m) above sea level, within the São João River Basin of Rio de Janeiro state, not far north of the city of Rio de Janeiro. Annual rainfall here is about 59 in (150 cm).
Parenthood rescinded. The golden lion tamarin was once considered to be the parent species of three other lion tamarins who also reside within Brazil’s Atlantic Forest: the golden-headed lion tamarin, aka golden-headed tamarin (Leontopithecus chrysomelas); the black lion tamarin, aka golden-rumped lion tamarin (Leontopithecus chrysopygus); and the black-faced lion tamarin, aka Superagüi lion tamarin (Leontopithecus caissara). Today, however, each of these lion tamarins is recognized as a distinct species, rather than as a subspecies or “child” of the golden lion tamarin.
All four lion tamarin species belong to the family Callitrichidae, which comprises more than 60 members who include non-lion tamarins and marmosets.
Size, Weight, and Lifespan
Golden lion tamarins weigh a mere 14–29 oz (0.4–0.8 kg) and have a head-to-body length of 7.5–8.75 in (19–22 cm), with little size difference between males and females. A non-prehensile tail adds another 10.25–13.5 in (26–34 cm) to their tiny frame.
In the wild, golden lion tamarins are known to live from 10 to 15 years.
Belonging to the same species.
A species selected to act as an ambassador, icon, or symbol for a defined habitat, issue, campaign or environmental cause.
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A lustrous, golden mane, evocative of Africa’s lion king, frames the golden lion tamarin’s expressive dark and hairless face. Almond-colored eyes view the world, while widely spaced nostrils, set in a flat and unassuming muzzle, breathe in the scents of the jungle. The skin above its narrow lips (known as the philtrum) is decorated with random white hairs. A silky, long-haired golden coat overwhelms this tiny primate’s body, and its long tail, hands, and feet are either brown or black.
While most New World monkeys have claws on all their digits, Mother Nature has fitted golden lion tamarins with modified claws on all digits—except for their big toes, which she has given nails. Their thumbs are non-opposable. If you could peek inside their mouths, you’d see two molar teeth on either side of each jaw (rather than three, as common with most New World monkeys). Their tiny marmoset “cousins” share these physical anomalies.
Golden lion tamarins are omnivores (consuming both plant and animal foods) whose varied diet consists of flowers, fruits, nectar, plant exudates (gums), bird eggs, snails, spiders, and insects. Insects are a key source of chitin, a fibrous substance that promotes the absorption of calcium and other important minerals. Favorite plants of the species are in the Bromeliacae family—not because the monkeys find these plants tasty, but because these plants are loaded with insects, whom the tamarins devour.
Food selection is dependent upon microhabitat. During the rainy season, these tiny monkeys feast mainly on pulpy fruits; an additional 10 to 15 percent of their meals come from insects. During the dry season when insects are not abundant, golden lion tamarins eats nectar, along with small frogs and lizards. Like marmosets, tamarins have a high metabolic rate.
Behavior and Lifestyle
As with all members of the larger Callitrichidae family, golden lion tamarins are gifted with impressive cognition. These primates appear to keep a “cognitive map” of their environment that guides them as they travel. They are further aided by their exceptional visual, olfactory, and auditory perceptual capabilities.
An arboreal species, golden lion tamarins spend the vast majority of their time in trees, rarely descending to the ground. They move through the forest canopy by leaping, bounding, running, or walking along tree branches, using their feet and hands in a form of locomotion known as “arboreal quadrupedalism.” Their claws allow them to cling to tree trunks, while their long tails help them to balance. Golden lion tamarins’ branch-hopping agility and acrobatics have drawn comparisons to that of squirrels.
Engaging in an activity described by scientists as “micromanipulation,” these little primates make further practical use of their claws to dig deep inside crevices, probe beneath palm leaf sheaths, and investigate rotted logs to capture insects and other small prey. Because golden lion tamarins are not fitted with the type of dentition that allows them to gouge tree bark to stimulate the flow of exudates, they opportunistically wait for other animals to create these flows.
Active during daylight hours (making them “diurnal”), golden lion tamarins spend 9 to 12 hours each day foraging for food, eating, resting, playing, and grooming one another. Peak feed times are just before sunset and immediately after they arise each morning.
Overnight, these monkeys sleep together as a family, hidden deep inside tree hollows. Periodically, a family changes its sleeping site to reduce the chance of being discovered by predators such as hawks, other raptors, and large snakes. Adults are the first to waken each morning and the last to go to bed.
Golden lion tamarins are a species of dwarf monkey, whose membership Mother Nature has coiffed with elaborate hairdos.
It is thought that the golden lion tamarin gets its hair color from sunlight and from carotenoids (the yellow to red pigments) in its food.
Evolution and natural selection have been proffered as explanation as to why golden lion tamarins, believed to have descended from much larger primates, nearly always give birth to twins. The monogamous relationships between parents are also thought to be based upon their evolution.
An average of eight individuals including at least one breeding adult male and one breeding adult female, along with subadults, juveniles, and infants, comprise a social family group, known as a “troop.” Larger family groups may include two or three adult males and one adult female, or two to three adult females and one adult male. Adult females inherit rank from their mothers and are dominant over new males who join the troop.
Both males and females typically leave their familial group at age four, when they seek to establish their own families or establish social rank within another existing troop. But they don’t venture too far from their home range; average dispersal distance is just 0.5 mi (0.85 km).
Home range varies from 0.15–0.4 sq mi (0.4–1 sq km), depending on troop size (with larger troops occupying larger home ranges). Other determinants include predation risk and presence of potential breeding partners.
Some of the charismatic species who share the golden lion tamarin’s range include woolly spider monkeys (also known as muriquis), red-tailed parrots, and maned three-toed sloths.
In conducting a population census, scientists from Brazil’s Associação Mico-Leão-Dourado (AMLD) (Golden Lion Tamarin Association) played prerecorded golden lion tamarin vocalizations to elicit responses from troops throughout the primates’ geographic range. The scientists found that these tiny monkeys communicate with one another through a repertoire of vocalizations. Besides conveying specific information, vocalizations facilitate social bonding.
“Peeps” signify alliances, whereas “whines” are associated with alarm. During foraging excursions or aggressive encounters, golden lion tamarins “cluck.” To communicate their location over long distances, golden lion tamarins call out to one another with “trills.”
Youngsters often emit “rasps” or “screeches” while playing. Playtime is not just about fun; social play is an important aspect of juvenile behavior that helps to develop cognitive, motor, and survivorship skills.
Olfactory communication is another important communication tool for golden lion tamarins, whom Mother Nature has fitted with specialized scent glands in their anogenital region, suprapubic area (above the pubic bone), and above the sternum (breastbone). Oily secretions from these glands are mixed with urine and genital discharge to convey specific messages. By leaving their scent upon a substrate in their environment, information about identity, social rank, and hormonal changes is revealed.
Social and sexual interactions are influenced through scent marks. For example, both reproductive males and females scent-mark their territories, including their sleeping sites. Males engage in this behavior to claim social rank, thereby discouraging rival reproductive males. Females engage in this behavior to suppress the ovulation of other adult females in her troop.
Scent-marking is also used to demarcate home range boundaries of this territorial species. Scientists have found that scent-marking increases when conspecific intruders are present and during territorial encounters with these “outsider” individuals. Should an intruder present himself, golden lion tamarins exhibit intimidating body language and postures: an open mouth, staring, and an arched back are indicators of a pissed-off monkey.
As with most nonhuman primates, the practice of grooming one another (known as “allogrooming”) serves multiple purposes. Certainly, combing through and picking out detritus from one another’s fur coat improves the overall hygiene of all troop members. But this tactile activity is also key in establishing and strengthening social bonds with one another. Mutual grooming sessions are known to reduce tensions and stress, resolve conflict, and serve as foreplay to sexual activity.
Some anthropologists and primatologists have posited that allogrooming in early humans served as a precursor to language. They further suggest that, with evolution, humans abandoned this practice and question whether we humans have deliberately denied ourselves this intimate act because it reminds us of our own innate animal nature.
Because of their anatomical and reproductive characteristics, tamarins (like marmosets) are considered to be primitive monkeys. Females attain sexual maturity (able to conceive and bear young) at about 18 months of age; males lag behind a bit, attaining sexual maturity (able to sire young) at about 24 months of age.
Only the dominant female reproduces. While the estrogen cycles of subordinate females are synchronized with that of the dominant female, their estrogen concentrations are much lower, leaving them unable to conceive. To ensure that these other females remain “barren,” the dominant female leaves pheromonal cues in her scent-mark secretions, declaring her status as the troop’s only breeding female.
A monogamous species, male and female golden lion tamarin partners bond for life. Typically, a couple breeds twice a year, between September and March. Twin births are the norm after a gestation period of about 4.5 months.
At least 3 months after she gives birth, a female is capable of becoming pregnant again. Although shorter birth intervals increase the number of offspring, these infants suffer a higher mortality rate. In fact, the infant mortality rate for golden lion tamarins is nearly 50 percent. Longer interbirth intervals increase the chances for more robust offspring.
Golden lion tamarins are born fully furred with their eyes open. These infants benefit from “alloparenting.” Child-rearing is a family affair, with everyone helping out. Fathers, and other troop members, give mothers a break from nursing by carrying the tiny babies on their backs. At about 4 weeks of age, infants begin begging for solid food from those who are carrying them. Gracious creatures, these family members willingly share food with the little ones and with one another, an act of etiquette that helps to cultivate and sustain social bonds.
By 90 days of age, young golden lion tamarins are considered fully weaned. Thanks to the munificence of their caregivers, these youngsters have learned to recognize which foods are healthy to eat, and which to avoid.
Golden lion tamarins are ecological ambassadors, helping to regenerate their forest habitat. The seeds of the many fruits they eat pass through the monkeys’ digestive tracts and are distributed, via their feces, throughout their environment, resulting in new forest growth and providing resources for more animals.
The golden lion tamarin is classified as Endangered by the International Union for Conservation of Nature (IUCN, 2015), appearing on the IUCN Red List of Threatened Species, having been down-listed from Critically Endangered in 2003. This slight improvement is due to its increased population, from less than 200 in the 1960s—when the golden lion tamarin was on the brink of extinction—to a reported 3,200 in 2014 according to a census conducted by AMLD. Tragically, more than a third of this population succumbed to an outbreak of yellow fever in 2017. While the majority of humans in the area had been vaccinated and, thus, protected against the ravaging effects of this mosquito-borne disease, no such vaccine had been available to golden lion tamarins. Today (2022), the species’ wild population is around 2,500 individuals—about a third are descendants of golden lion tamarins who were raised in human care (see Conservation Efforts, below, for how innovative global collaborations saved the species from extinction).
Loss of habitat remains the greatest threat to the golden lion tamarin’s survival; today, the species subsists on only 2 percent of its original territory. Humans have pillaged forests through clear-cutting for timber, charcoal production, cattle ranching, agriculture, and, more recently, urban expansion.
With the influx of humans has come potentially catastrophic diseases. Tamarins and marmosets are susceptible to measles, mumps, and other human diseases that can be fatal to these tiny primates. In captive populations, toxoplasmosis has proven deadly.
The species’ sad history includes capture by bad actors of zoos, research laboratories, and the illicit pet trade—all ignominious contributors to the golden lion tamarin’s near demise. Fortunately, illegal capture of golden lion tamarins has nearly ceased since conservation efforts began in earnest.
Our earth’s climate crisis looms like a specter over this species. Even those monkeys who live in so-called “protected” areas are not safe from this potentially catastrophic occurrence. Scientists predict that, unless we humans get serious about making environmental changes, by 2080 golden lion tamarins will lose roughly 87 percent of their already diminished suitable habitat.
Golden lion tamarins are listed in Appendix II 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.
Since its founding in 1992, the Brazilian nonprofit organization AMLD (which developed from the Golden Lion Tamarin Conservation Program) has dedicated itself to the preservation of the golden lion tamarin. As the lead organization in this conservation effort, AMLD’s locally based team includes conservation biologists, wildlife managers, environmental educators, and members from the local community.
Save The Golden Lion Tamarin (SGLT), a U.S.-based nonprofit, provides technical support and raises funds for AMLD. The organization is committed to cultivating worldwide awareness and concern for this tiny primate.
A collaborative scientific endeavor by research institutions and several primate conservation groups, including AMLD and SGLT, led to the development of a yellow fever vaccine. In October 2018, the first wild golden lion tamarins were vaccinated, giving them protection against this potentially fatal disease.
Golden lion tamarin conservation efforts include education, sustainable agriculture, reforestation programs, the planting of “corridors” that reconnect fragmented environments, and scientific management of the wild population to minimize inbreeding.
Partnerships with Zoos and Translocation
Innovative partnerships with conservation-minded zoos around the world have helped to dramatically increase the golden lion tamarin population. Successful captive breeding programs with subsequent reintroduction of golden lion tamarins into their natural habitat have prevented these primates from disappearing from the face of the earth. Zoos with an existing collection of the species, prior to the start of this specific conservation effort, have also been able to play a redemptive, positive role in saving the golden lion tamarin.
One zoo that continues to play an important role in golden lion tamarin conservation, with a success record for reintroducing these primates into the wild, is Apenheul, located in the Netherlands. A member of the European Endangered Species Program (EEP), Apenheul is credited with establishing the Apenheul Primate Conservation Trust (APCT) in 1994. Monies from this trust are used to support nature conservation projects to protect primates and their habitats in the wild.
Translocation—transferring golden lion tamarins from isolated, unsafe pockets of forests to larger, protected forests—has also helped to ensure the survival of this species.
Reintroduction and translocation do not come without risks, however. These golden lion tamarins are susceptible to contracting diseases for which they have had no previous exposure. Scientists closely monitor these conservation efforts to help ensure the primates’ survival.
According to population biologists, to prevent this species from becoming extinct, a population of 2,000 golden lion tamarins living in the wild requires 62,000 acres (25,000 hectares) of protected and connected forest. If the forests disappear, then so will the golden lion tamarin.
Sustained international awareness is paramount in ensuring the golden lion tamarin’s future. As recently as February 2016, dubious legislation was quietly filed at the behest of powerful and wealthy landowners with an interest in further developing forestland for agribusiness. This legislation could have revoked Brazil’s 2014 Ministry of the Environment Endangered Species Legislation—thereby placing the golden lion tamarin, along with other species, in grave peril.
The Brazilian Congress was set to vote on this proposed legislation just before the start of Carnaval, the country’s national four-day celebration. Fortunately, AMLD learned of this legislation, immediately mobilized its global partners, including zoos, and spread the word internationally to all its supporters. An online petition decrying this dubious legislation garnered more than 11,000 signatures in 10 days, 90 percent from Brazilian citizens. An ensuing global firestorm in social media ultimately forced the withdrawal of this legislation, which had the devastating potential of becoming a death knell for the golden lion tamarin.
In 2018, the Brazilian government officially declared August 2 as National Golden Lion Tamarin Day.
- https://nationalzoo.si.edu/scbi/EndangeredSpecies/GLTProgram/Learn/default.cfm http://www.nhptv.org/wild/callitrichidae.asp
Written by Kathleen Downey, May 2022