Sunday, December 7, 2014

The Golden Monkeys of the New World

Source: Google Images
Species:L. rosalia
The golden lion tamarin, Leontopithecus rosalia, is an endangered primate native to the Atlantic Forest of Brazil, in South America. However, its habitat has been reduced to approximately 5% of its original size due to deforestation, predation, and illegal poaching. Luckily, through conservation efforts, translocation, and reintroduction programs, this little monkey is making a comeback along the coastal areas of Brazil and its numbers are slowly increasing.

The golden lion tamarin belongs to the family callitrichidae, a group of new world monkeys that includes marmosets and tamarins. It is the largest of the callitrichines, weighing in at approximately 1.3 pounds and the length of their body being somewhere between six and ten inches, not including the ten to sixteen inch tail. They get their name from the distinctive reddish gold hairs that surround their face and ears, creating a brilliant mane around their dark, hairless face. The golden color of their hair is thought to be caused by the sunlight and the organic pigments found in their food. Unlike old world monkeys and apes, who have flat finger and toe nails, the golden lion tamarin and all other new world monkeys have tegulae (1), small claw-like nails that allows the monkey to easily cling to the bark of trees and branches. Their sharp claws, combined with their prehensile tail, are the monkeys mode of transportation, allowing them to quickly travel among the branches in which they live, jumping from tree to tree, and even running, squirrel-like, through the treetops. Golden lion tamarins are not sexually dimorphic, so both male and the female monkeys are both relatively the same size and color.

In the wild, golden lion tamarins live in groups of two to eleven, with the average group number ranging around five. However, average group sizes have decreased in recent years due to high levels of predation. The social structure of the group varies, but always includes one dominant male and female breeding pair. Most dominant males are monogamous, breeding with only one female, but occasionally they will exhibit polygamous behavior and breed with two females, usually a mother/daughter pair. In addition to the ruling pair, there will be several subadult, juvenile, and infant members of the group that are usually offspring of the dominant breeding pair. If there is more than one adult male in the group, one asserts his dominance over the other via physical violence and by
Source: The Guardian
"arch walking", where the dominant male will arch his back while walking on all fours, much like a frightened cat. Dominant relationships among the group are determined by a seniority ranking. Those who have been in the group territory longer have a higher hierarchical ranking. For example, if an immigrant male finds his way into the group, a young female who has inherited her mother's breeding position will have dominance over him. Furthermore, females within a group may be related to one another, but males can be non-natal, which is to say they were not born into the group. The logic behind this hinges on the dispersal patterns of adult monkeys. At the age of four, both males and females leave their original group, forming single sex groups and looking for a group they can immigrate into. However, in order to do so, a vacancy must appear in a group, leaving a spot open to be taken over by a new member. For example, if a dominant female dies, her daughter moves up to take her place. Rather than mating with his daughter, the dominant male moves out, leaving an open space available for a new male to move up in rank or an immigrant male to move in. An immigrant male may also take over a group by challenging the reigning, male leader and winning. Two males, usually brothers are sometimes observed taking over a group, while one becomes dominant and asserts his power over the other. Unfortunately for females, those who disperse do not often make it into a new group and usually die or disappear before finding a new home. However, family groups are hostile towards one another, with the dominant male and female behaving violently towards imposing strangers and trespassers (3).

Golden lion tamarins are omnivorous, eating everything from fruits and flowers to birds eggs, insects, and small vertebrates. Although much of their original habitat has been destroyed, small microhabitats exist within their current range, including bromeliads, vine tangles, and rotting logs, that are important to the monkeys' foraging habits and living patterns. The tamarins use their elongated fingers to catch small prey hiding in crevices and underneath leaves. Insects, however,only make up approximately 15% of their diet, while a considerably larger portion of their diet consists of fruit, found in the leafy tree tops. During the dry season, when fruit and insects are not as abundant, they must rely on other sources of food, such as nectar, gum, and small animals, usually reptiles.
Source: Flickr
Because of their reliance on insects and fruit as a food source, golden lion tamarins are often referred to as fauni-frugivores, an animal that specializes in eating fruits.  Also, because they feed on fruits and flowers, they are important to plant germination and seed dispersal. Acting as a transportation device for pollen and seeds (4). The monkeys spend their days foraging food, starting with fruit in the morning and moving on to foraging for insects and resting in the afternoon. As the afternoon progresses, they spend the rest of the day traveling to their nighttime nesting sights, where they sleep in groups, usually in hollow tree cavities or in dense vines. During the warmer, wetter season, the tamarins start their foraging earlier and end it later than they do during the colder, drier season. Although most callitrichines depend on gums and saps as a staple part of their diet, golden lion tamarins only rely on them as a supplementary source, only eating it when other food sources are low.

Habitat and Distribution:
The golden lion tamarin is native to the rain forests of Eastern Brazil, specifically, the Atlantic Coastal Forest. Because of deforestation, they have lost all but approximately 5% of their original habitat and are now limited to three specific areas, Poço (POH-so) das Antas Biological Reserve, Fazenda União Biological Reserve, and some private land through the Reintroduction Program. In Poço das Antas (5), they prefer swamp jungle, situated no more than 300 ft. above sea level, which contains many vines, bromeliads, and a high density of both fruit and animal food sources. Because
Source: Wikipedia

all of this land originally fell victim to the logging industry, it is not as it once was, so it is not well known what the monkeys preferred before they were thrust into that situation. It is assumed that they preferred a humid, closed canopy forest with a large amount of vegetation that would provide pathways through the trees and protection from airborne predators. A population estimate back in 1972 decided that there were approximately between 400 and 500 golden lion tamarins in the wild. A more recent count in 1981 determined the number to be less than 200 and an even more recent estimate has found that numbers have increased to be, at most, 400 individuals (2). 

The golden lion tamarin was first placed on the endangered species list by the International Union for Conservation of Nature (IUCN) in 1982. Not long after, in 1984, the National Zoological Park in Washington D.C. and the World Wide Fund for Nature (WWF) started a reintroduction program through the Golden Lion Tamarin Association. This program enlisted the help of 140 zoos, worldwide, to breed and reintroduce golden lion tamarins back into the wild in order to boost wild populations. Despite the success of this project, the IUCN increased the level of endangerment to critically endangered in 1996. Deforestation, illegal poaching, and urbanization are some of the main reasons that there has been such a sharp decline in numbers. However, organizations, such as the Nation Zoo, has worked diligently to help bring these numbers back up, through specialized breeding programs, reintroduction, and translocation. By increasing the wild populations by reintroduction and maintaining large breeding groups in captivity, the conservation efforts have succeeded. However, deforestation and poaching are still fierce competitors and the battle is continual (1). 

Works Cited:
  1. Golden lion tamarin. (2014, November 30). Retrieved December 2, 2014, from
  2. About Golden Lion Tamarins - National Zoo| FONZ. (n.d.). Retrieved December 2, 2014, from
  3. Golden lion tamarinLeontopithecus rosalia. (n.d.). Retrieved December 2, 2014, from
  4. Lapenta, M. J., De Oliveira, P. P., Kierluff, M. C., & Motta-Junior, J. C. (2003). Fruit exploitation by golden lion tamarins (leontopithecus rosalia) in the uniao biological reserve, rio das ostras, rj - brazil. Mammalia. Retrieved from
  5. Leontopithecus rosalia. (n.d.). Retrieved December 8, 2014, from

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