GLT FAQs
1. What are Golden Lion Tamarins (GLTs) and what do they look like?
The golden lion tamarin (Leontopithecus rosalia), “mico-leão-dourado” in Portuguese, is a species of small monkey, weighing about 1.2 pounds and measuring about 35 inches from their nose to the tip of their tail. They have an impressive reddish-gold mane, from which they received their common name. They have long tails that help them balance as they propel themselves from branch to branch in the forest canopy. The long slender fingers on their hands help them dig in crevices for insects and small vertebrates to eat. They do not have opposable thumbs to grab branches, and they cannot hang by their tails.
2. Where do GLTs live?
The only place in the world where GLTs live is in the lowland portion of Brazil’s Atlantic Rainforest near the city of Rio de Janeiro in Southeast Brazil. Today, less than 2% of their original habitat remains, all fragmented into patches separated by cattle pastures, roads, and towns.
3. How long do GLTs live?
In the wild, they may live as long as 15 years, but very few get that old. In zoos they can live up to 20 years.
4. What do GLTs eat in the wild? What are GLTs fed in zoos?
Their diet in the wild consists of fruits, nectar, insects, and small vertebrates. Their long fingers help them reach into bromeliads and under tree bark to capture insects, small frogs, and lizards.
In zoos, they are fed, depending on their weight, age, health and preference: a special monkey gel, grapes, insects such as crickets and mealworms, and fruits and vegetables. They also receive a variety of other foods for enrichment and training.
5. When and where do GLTs sleep?
GLTs are diurnal (active during the daytime hours), spending most of their time in the middle portion of the forest canopy where they are safe from predators on the ground (like foxes) and from the sky (like hawks). At night, family groups retire to hollows in trees to sleep together. The adults are the first out of the holes in the morning and the last to enter at night, thus providing protection for the young.
6. What are GLT families like?
GLTs live in family groups with an average of 6 individuals. After a gestation period of 4 months, females typically give birth to twins. In the wild, the babies are born during the rainy season (October to March), when fruits are plentiful. The father and siblings help the mother raise the babies, often carrying the infants on their backs between feedings. Since a pair of twins can weigh as much as 20% of the mother’s weight, she can certainly use the help.
7. How many GLTs were there in 1970? How many GLTs are in the wild today?
By the early 1970s, centuries of deforestation and capture for the pet trade had reduced the population to fewer than 200 GLTs in the wild. By 2017, their numbers in the wild had risen to 3,700 and their official status had been upgraded from critically endangered to endangered. A survey in 2018 (Nature Scientific Reports 2019) found the population had fallen to 2,500 due to an outbreak of yellow fever that spread among people and monkeys throughout Southeast Brazil. The greatest reduction in GLT numbers due to yellow fever occurred in Poço das Antas Biological Reserve where numbers fell from 380 to 32. AMLD partners developed a yellow fever vaccine that was safe and effective for GLTs. AMLD field staff began vaccinating GLTs in October 2020. A new field survey completed in 2023 estimated the total number of GLTs at 4,800. These 4,800 GLTs live in 7 forest fragments that are isolated from one another by roads and cattle pasture that GLTs can’t cross.
8. How many GLTS are needed to save them from extinction?
Scientists have determined that a population of 2,000 tamarins living in the wild in 25,000 hectares (62,000 acres) of protected and connected forest is the minimum needed. Currently (2023) there are an estimated total of 4,800 GLTs in the wild, but these 4800 are divided in 7 populations isolated in the largest blocks of connected forest habitat. The largest population has 1,662 GLTs, 83% of the 2,000 GLTs needed to be safe from extinction.
9. How many zoos have GLTs? How many GLTs are there in zoos?
Today, over 150 zoos around the world have GLTs and participate in their conservation by maintaining an insurance population capable of recuperating the wild population from a potential disaster. Approximately 500 GLTs live in these zoos worldwide.
10. How do we ensure genetic diversity among GLTs in the captive population?
All GLTs in zoos are managed by a Studbook Keeper. The Studbook Keeper maintains the pedigree records of all the captive GLTs and coordinates how the animals are paired to maintain maximum genetic diversity in the captive population.
11. Who is working to help save GLTs?
The Associação Mico Leão Dourado (AMLD - golden lion tamarin association) was established in 1992 as a Brazilian non-profit organization with a mission of saving the GLT from extinction while maintaining the well-being of the local people. AMLD coordinates implementation with many partners of a long-term multi-faceted strategic plan to detect and reduce threats to the species. This locally-based Brazilian team includes conservation biologists, wildlife managers, GIS technicians, environmental educators, foresters, agroecologists, and local landowners. Save The Golden Lion Tamarin (SGLT) was established in 2005 as a U.S. charitable non-profit organization to provide technical and financial support to AMLD. And of course, committed citizens around the world also provide financial support so the work of conserving this precious species can be carried out.
12. Why do you put radiocollars on some GLTs? How do you catch them to do that?
AMLD biologists attach very small radio-transmitter collars to 1-2 GLTs in each family group. These radios emit high-frequency “beeps” that allow the observers to find them, even in dense forest. The observers can then follow the GLTs wherever they go, recording their behavior and noting any threats. AMLD biologists use live traps baited with fruit to safely capture GLTs to change the transmitter collars when batteries run out (approximately every 6 months). Soon after the radio collars are attached the GLTs are released at the place where they were captured.
13. What would be affected if GLTs went extinct?
GLTs are considered an "umbrella species" as their conservation ensures saving many other species in the same habitat. Today, GLT distribution is restricted to 8 municipalities 100km (62 miles) from Rio de Janeiro city. Even in its reduced state, the Atlantic Forest has enormous social, economic, and environmental importance: 52% of Atlantic Forest trees, 92% of its amphibians and at least 158 bird species are found nowhere else in the world. Eighteen of Brazil’s 77 primate species, including GLTs, are found only in the Atlantic Forest. The watershed that contains nearly all wild GLTs also provides fresh water to approximately one million people in local communities. If we lose GLTs it will be because we have lost their forest. Forest protection benefits tamarins, thousands of other species, including people. Restoring forest helps reduce climate change and benefits the entire planet.
14. Is there a vaccine to protect GLTs from Yellow Fever?
Yes, partners of AMLD who are experts in combating viruses, recently modified an existing vaccine to protect golden lion tamarins from yellow fever — the first such vaccine for a non-human primate. The AMLD field team began vaccinating wild golden lion tamarins in October 2020. By the end of 2023, they had vaccinated 448 individuals, protecting them for life against the disease.
15. Can GLTs contract COVID-19, caused by the new coronavirus?
We don’t know if GLTs are susceptible to COVID-19, but AMLD is working under the assumption that GLTs can contract the disease and is taking every precaution to ensure that they are not exposed to it. When near GLTs, AMLD staff wear masks and gloves, and close contact with GLTs is minimized. Brazilian and international experts are advising AMLD on precautions concerning COVID-19.
16. How many species of lion tamarins are there?
The Golden Lion Tamarin is one of four lion tamarin species that make up the genus Leontopithecus. Each species lives in a different section of what remains of the Atlantic Forest of Brazil. The Golden lion tamarin (Leontopithecus rosalia) lives only on the coast of the state of Rio de Janeiro. The Golden-headed lion tamarin (Leontopithecus chrysomelas) lives only in the southern portion of the state of Bahia. The Black lion tamarin (Leontopithecus chrysopygus) lives in the western portion of the state of São Paulo. The Black-faced lion tamarin (Leontopithecus caissara) lives on the coastal border between the states of São Paulo and Paraná. The Golden, Golden-headed and Black lion tamarins are classified as endangered species. The Black-faced lion tamarin is considered critically endangered.
