INTRODUCTION:
There are several species of tamarins as you will notice in the list below. In this month’s creature feature we will however focus on a friend of Monkeyland’s favourate tamarin specie – the Saddle-back tamarin:
HABITAT: Brazil, between Solimoes River and Ica River, Sao Paulo de Olivenca
LONGEVITY RECORD: 24.5 years
MALE SEXUAL MATURITY: 730 days
FEMALE SEXUAL MATURITY: 546 days
GESTATION PERIOD: 140 to 150 days
LITTER SIZE: 2 (viviparous)
WEIGHT AT BIRTH: Approximately 40grams
ADULT WEIGHT: Approximately between 300 qnd 450grams
PHYSICAL DISCRIPTION: Saddle-backed tamarins are generally a rust color with a distinctive black head and white muzzle. They have very little sexual dimorphism in mass. Like all tamarins, they have a long, but not prehensile, tail. They have clawed digits (except for the hallux) and no opposable thumb.
Unlike the marmosets, this species, like all tamarins, have canines that are larger than the incisors, and their teeth morphology does not allow them to gnaw into the bark for gum (exudates) like the marmosets. The average adult body mass is about 310 grams.
HOME RANGE: The saddle-back tamarin is found in the following countries: Bolivia, Brazil, Colombia, Ecuador, and Peru. This species is found to inhabit primary and mature secondary rainforests, in trees from 3-20 meters in height.
ECOLOGY: The saddle-back tamarin forages for a number of food items including: insects, ripe fruits, gum (exudates), and nectar. When they feed on exudates (gum) they cling vertically with their claws embedded into the bark of the tree. They can only forage upon exudates (gum) that is already coming out of the tree by other means. The dominant female of the group usually controls the access to the area on the tree where the gum (exudates) are coming out of (Garber, 1993). The saddle-back tamarin also feeds upon large, cryptic invertebrates in all levels of the forest canopy, and uses a vertical clinging posture. The group of the saddle-back tamarin numbers from 3-8 individuals. This is an arboreal species.
LOCOMOTION: This diurnal species walks or runs quadrupedally through the forest, and is capable of leaping between branches. This species can also cling to the side of the tree, embedding its claws into the bark.
SOCIAL BEHAVIOUR: The saddle-back tamarin has a multimale-multifemale social system. The groups consist of unrelated adults, and the main mating system is polyandry, with monogamy and polygyny being reported. The offspring are cared for by all adult group members, which includes the males. Group members also feed the infants, allowing the infants to take food from them.
The group sleeps huddled together, which occurs in vines or branches. The saddle-back tamarin forms mixed-species associations with Saguinus imperator. The saddle-back tamarin also forms mixed-species associations with Saguinus mystax, Saguinus labiatus, and Saguinus nigricollis. These mixed-species associations may serve to assist in protecting from predators.
REPRODUCTION: The saddle-back tamarin gives birth to twins like most callitrichids.
The majority of social groupings consist of one female, more than one male, and young. This polyandrous organization probably results from the unique reproductive system of tamarins. In groups with one female and two males, both males usually mate with the female and each cares for one of the resulting offspring. Juvenile saddle-backed tamarins also engage in helping behavior, carrying and feeding the infants. These behaviors help the mother to cope with the demands of lactation, which are quite high.
In the saddle-back tamarins, the dominant breeding female suppresses the other females from having ovarian cycles, and this may also be accomplished by scent. It was found that when they exposed the family scent to a female who had left the family group and paired that she would have a delay in her ovarian cycle.
The reproductive system is the most interesting aspect of tamarin biology. Saddle-backed tamarins come into sexual maturity at the age of 23 months. Their gestation period is 140-150 days and the interbirth interval is about 12 months, although captive tamarins are capable of reproducing twice each year. All this is unextraordinary. The amazing part is the size and number of offspring. The majority of births are twins whose total weight is almost one-quarter that of the mother`s. It is thought that this fact is a major contributing factor to the tamarin`s polyandrous social organization. Or it is possible that polyandrous care-taking of infants led to the evolution of twin births and exceptionally high birth weights.
VOCAL COMMUNICATION:
contact call: This call by the saddle-back tamarin is used to keep track of the whereabouts of other members of the group.
OLFACTORY COMMUNICATION:
Pregnant females tend to scent mark frequently, and this might help in bringing the group together so helpers are there when the infants are born.
circumanal marking: This is when a saddle-back tamarin rubs the substrate with the circumanal areas in a sitting position; this is the most frequent marking behavior for this species.
suprapubic marking: This is when an individual presses the suprapubic pad against a substrate and deposits secretions by pulling itself along or by pushing itself with its feet.
sternal marking: This is when a saddle-back tamarin rubs the sternal gland against a substrate.
THREATS: Loss of habitat due to deforestation would be the main threat to the saddle-backed tamarins. The second largest threat is the human, because they are commonly captured for the pet trade.
