GLT FAQs

1.  What are Golden Lion Tamarins (GLTs) and what do they look like?

Golden lion tamarins (Leontopithecus rosalia) are a species of small monkey, weighing about 1.5 pounds and measuring about 25 inches long from their head to tip of their tail.  They have an impressive reddish-gold mane, from which they received their common name. Their Portuguese name is Mico-leão dourado.  They have long tails that help them to balance as they propel themselves from tree to tree in the forest canopy.  The long slender fingers on their hands help them to dig in crevices for insects and small vertebrates to eat. 

2.  Where do they live?

The only place in the world where they live is near the city of Rio de Janeiro, Brazil, in the lowland portion of the Serra do Mar Atlantic Forest.  Today, less than 2% of their original habitat remains.

3.  How long do they live?

In the wild, they may live as long as 10-15 years.  In captivity they can live up to 20 years.

4.  What do they eat?

Their diet consists of fruits, insects, and small vertebrates.  Their long fingers help them reach into the center of plants to capture insects, small frogs, and lizards.

5.  When and where do they sleep?

GLTs are diurnal (active during the daytime hours), spending most of their time in the trees.  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 to the young.

6.  What are their families like?

They live in family groups with an average of 6 animals.  After a gestation period of 4 months, females generally give birth to twins.  The father and siblings help the mother in raising 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 of them were there in the wild by 2012?

By the early 1970s, there were fewer than 200 GLTs in the wild, making them critically endangered with extinction.  About 1700 GLTs live today in the largest remaining forest fragments, including the Poço das Antas Biological Reserve and the União Biological Reserve, and several private reserves near the city of Rio de Janeiro.

8How many GLTS are needed to save GLTs 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 needed.  In 2001, a major milestone was achieved when the population in the wild reached 1,000 GLTs.

9.  What are the main threats to GLTs?

Through the 1980s, loss of habitat due to logging and conversion of their forest for agriculture, as well as capture for zoos and the pet trade reduced the population of GLTs presented the main threats.  Today habitat loss and fragmentation due to urban expansion is the main threat.  In the wild, natural predators include hawks and other raptors, cats, and large snakes.

10.  How many zoos have GLTs in captivity? How many GLTs are there in zoos?

Today, over 150 zoos around the world have GLTs and participate in their conservation. Approximately 500 GLTs live in these zoos worldwide.  

11.  How do we ensure genetic diversity among the captive population? 

All GLTs in captivity are legally owned by Brazil and are managed by a Studbook Keeper at the National Zoo.  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.

12.  Who is working to help save GLTs?

The Associação Mico Leão Dourado (AMLD) was established in 1992 as a Brazilian non-profit organization that has a locally-based team of about 40 Brazilians.  These include conservation biologists, wildlife managers, GIS technicians, environmental educators, local community members and much more.  Save The Golden Lion Tamarin (SGLT) was established in the U.S. as a charitable non-profit organization to provide technical and financial support to AMLD.   And of course committed citizens whose donations provide the necessary financial support so the work of conserving this precious species can be carried out.

13.  What would be affected if the GLT went extinct?

GLTs are considered to be "umbrella species" as their conservation ensures saving many other species in the same habitat.  Today, GLT distribution is restricted to 8 municipalities 100km 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 it's forest.  Forest protection benefits tamarins, thousands of other species--and people.

14. How many GLTs were there before they start going extinct?

Let's assume that in 1500, GLTs occupied all of lowland Rio de Janeiro State, i.e. below 500m elevation ( we know the GLT elevation tolerance from AMLD/SGLT field work).  Rio State is approximately 44,000 km2 in area. Of that area, about 1/3 is 500m or less in elevation (rough guess by me. Here's where GIS could help).  So, prior to deforestation, about 14,667 km2 would have been suitable for GLTs.  Let's use 14,000 km2 to allow for some areas, such as lakes, that would not have been suitable--and to make the math easier.  14,000 km2 equals 1,400,000 hectares.  From three decades of studying territory sizes of GLTs, we (AMLD/SGLT) have good estimates of GLT densities in "suitable forest".  To be conservative, I will use the lowest observed density figure, 0.073 GLTs/hectare.  So, my estimate of the number of GLTs in Brazil in 1500:

0.073 GLTs/hectare  x  1,400,000 hectares of suitable forest  =  102,200 GLTs

Rounding down, let's say there was an estimated 100,000 GLTs, in about 17,000 breeding groups, before habitat destruction started.  Thus, the current population of 3,200 in 2018 is about 3% of what it once was.