The golden lion tamarin (Leontopithecus rosalia, Brazilian Portuguese: [ˈmiku ʎiˈɐ̃w̃ dowˈɾadu], mico-leão-dourado) also known as the golden marmoset, is a small New World monkey of the family Callitrichidae. Native to the Atlantic coastal forests of Brazil, the golden lion tamarin is an endangered species with an estimated wild population of approximately 1,500 individuals spread between 3 different locations along southeastern Brazil, and a captive population maintained at approximately 490 individuals among 150 zoos.^[4][3]

Physical characteristics

Closeup on the golden lion tamarin's face

The golden lion tamarin gets its name from its bright reddish orange pelage and the extra long hairs around the face ears which give it distinctive mane.^[5] Its face is dark and hairless. It is believed that the tamarin gets hair color from sunlight and carotenoids in its food.^[6] The golden lion tamarin is the largest of the callitrichines. It is typically around 261 mm (10.3 in) and weighs around 620 g (1.4 lb). There is almost no size difference between males and females. As with all callitrichines, the golden lion tamarin has tegulae, which are claw-like nails, instead of ungulae or flat nails found in all other primates, including humans. Tegulaes enable tamarins to cling to the sides of tree trunks. It may also move quadrupedally along the small branches, whether through walking, running, leaping or bounding.^[7] This gives it a locomotion more similar to squirrels than primates.

Habitat and distribution

The golden lion tamarin has a very limited distribution range, as overtime they've lost all but 2–5% of their original habitat in Brazil.^[8] Today, this tamarin is confined to three small areas of the tropical rain forest in southeastern Brazil: Poço das Antas Biological Reserve, Fazenda União Biological Reserve, private land through the Reintroduction Program.^[4] The first population estimate made in 1972 approximated the count at between 400 and 500. By 1981 the population was reduced to less than 200. Surveys from as recent as 1995 suggest that there may only be at most 400 Golden Lion Tamarins left in the wild. Tamarins live along the far southeastern border of the country in the municipalities of Silva Jardim, Cabo Frio, Saquarema, and Araruama.^[9] However, they have been successfully reintroduced to the municipalities of Rio das Ostras, Rio Bonito, and Casimiro de Abreu.^[10] Tamarins live in coastal lowland forests less than 300 m (984 ft) above sea level.^[11] They can be found in hilltop forests and swamp forests.

Behaviour and ecology

The Golden lion tamarin is for a maximum of 12 hours daily. It uses different sleeping dens each day.^[12][13] By frequently moving their sleeping nests around, groups minimize the scent left behind, reducing the likelihood of predators finding them.^[14] The first activities of the day are traveling and feeding on fruits. As the afternoon nears, tamarins focus more on insects. By late afternoon, they move to their night dens.^[12] Tamarin groups use hollow tree cavities, dense vines or epiphytes as sleeping sites. Sites that are between 11 and 15 m (36 and 49 ft) off the ground are preferred. The golden lion tamarin tends to be active earlier and retire later in the warmer, wetter times of the years as the days are longer.^[12] During drier times, it forages for insects longer as they become more scarce.^[12][13]

The golden lion tamarin has a diverse, omnivorous diet consisting of fruits, flowers, nectar, bird eggs, insects and small vertebrates. They rely on microhabitats for foraging and other daily activities and tamarins will use bromeliads, palm crowns, palm leaf sheaths, woody crevices, lianas, vine tangles, tree bark, rotten logs, and leaf litters.^[12][13] The golden lion tamarin uses its fingers to extract prey from crevices, under leaves, and in dense growth; a behavior known as micromanipulation.^[15] It is made possible by elongated hands and fingers. Insects make up to 10–15% of its diet. Much of the rest is made of small, sweet, pulpy fruits.^[12] During the rainy season, golden lion tamarin mainly eat fruit, however during drier times, it must eat more of other foods like nectar and gums.^[12] Small vertebrates are also consumed more at these times as insects become less abundant.

Social structure

Family groups may consist of up to eight members.

Golden lion tamarins are social and groups typically consist of 2-8 members.^[16] These groups usually consist of one breeding adult male and female but may also have 2–3 males and one female or the reverse.^[16] Other members include subadults, juveniles and infants of either sexes. These individual are typically the offspring of the adults. When there is more than one breeding adult in a group, one is usually dominant over the other and this is maintained through aggressive behavior. The dominance relationship between males and females depend on longevity in the group. A newly immigrated male is subordinate to the resident adult female who inherited her rank from her mother.^[17] Both males and females may leave their natal group at the age of four, however females may replace their mothers as the breeding adult, if they die, which will lead to the dispersal of the breeding male who is likely her father.^[18] This does not happen with males and their fathers. Dispersing males join groups with other males and remain in them until they find an opportunity to immigrate to a new group. The vast majority of recruits to groups are males.^[18] A male may find an opportunity to enter into a group when the resident male dies or disappears. Males may also aggressively displace resident males from their group; this is usually done by two immigrant males who are likely brothers. When this happens, only one of the new males will be able to breed and will suppress the reproduction of the other.^[19] A resident male may also leave a vacancy when his daughter becomes the breeding female and he must disperse to avoid inbreeding.^[19] Golden lion tamarins are highly territorial and groups will defend their home range boundaries and resources from other groups.^[20]

Tamarins emit "whine" and "peep" calls, which are associated with alarm and alliances respectively.^[21] "Clucks" are made during foraging trips or during aggressive encounters, whether directed at conspecifics or predators.^[22] "Trills" are used to communicate over long distances to give away an individual’s position. "Rasps" or "screeches" are usually associated with playful behavior. Tamarins communicate though chemicals marked throughout their territories. Reproductive males and females scent mark the most and their non-reproductive counterparts rarely do so. Dominant males use scent marking to show their social status and may suppress the reproductive abilities of the other males.

Reproduction

The mother provides transportation at the early stages of the infant's life.

The mating system of the golden lion tamarin is largely monogamous. When there are two adult males in a group only one of them will mate with the female. There are cases of a male mating with two females, usually a mother and daughter.^[16] Reproduction is seasonal and depends on rainfall.^[23] Mating is at its highest at the end of the rainy season between late March to mid-June and births peak during the September–February rains.^[23] Females are sexually mature between of 15–20 months but it isn't until they are 30 months old when they can reproduce.^[22] Only dominant females can reproduce and will suppress the reproduction of the other females in the group.^[24] Males may reach puberty by 28 months.^[23] Tamarins have a four month gestation period. Golden lion tamarin groups exhibit cooperative rearing of the infants. It is due to the fact that tamarins commonly give birth to twins and to a lesser extent, triplets and quadruplets. A mother is not able to provide for her litter and needs the help of the other members of the group.^[25] The younger members of the groups may lose breeding opportunities but they gain parental experience in helping rear their younger siblings.^[17] In their first 4 weeks, the infants are completely dependent on their mother for nursing and carrying. By week five, the infant spend less time on their mother’s back and begin to explore their surroundings. Young reach their juvenile stage at 17 weeks and will socialize other group members. The subadult phase is reached at 14 months and a tamarin first displays adult behaviors.

Conservation status

Threats to the golden lion tamarin population include illegal logging, poaching, mining, urbanization and infrastructure development and the introduction of alien species. This species was first listed as endangered in 1982, rising to critically endangered in 1996.^[3] The Golden Lion Tamarins are also listed under Appendix I in CITES.^[26] By 2003 the successful establishment of a new population at União Biological Reserve enabled downgrading the species to endangered,^[27] but the IUCN warns that extreme habitat fragmentation from deforestation means the wild population has little potential for any further expansion.^[3] In an attempt to curb the golden lion tamarin's precipitous decline, several conservation programs have been undertaken. The intent is to strengthen the wild population and maintain a secure captive population in zoos worldwide. The survival rate of re-introduced animals has been encouraging, but destruction of unprotected habitat continues.

References