The common marmoset (Callithrix jacchus), also called white-tufted marmoset or white-tufted-ear marmoset, is a New World monkey. It originally lived on the northeastern coast of Brazil, in the states of Piauí, Paraíba, Ceará, Rio Grande do Norte, Pernambuco, Alagoas, and Bahia. Through release (both intentional and unintentional) of captive individuals, it has expanded its range since the 1920s to Southeast Brazil (its first sighting in the wild for Rio de Janeiro was in 1929), where it became an invasive species, raising concerns about genetic pollution of similar species, such as the buffy-tufted marmoset (Callithrix aurita), and predation upon bird nestlings and eggs.
The whole genome sequence of a female common marmoset was published on 20 July 2014. It became the first New World monkey to have its genome sequenced.
Physical description and morphology
thumb|left|Drawing of a marmoset
Common marmosets are very small monkeys with relatively long tails. Males are slightly larger than females; males have an average height of and females have an average height of . Males weigh on average and females weigh on average. The pelage of the marmoset is multicolored, being sprinkled with brown, grey, and yellow. It also has white ear tufts and the tail is banded. Its face has black across the nose-area skin and a white blaze on the forehead. The coats of infants are brown and yellow with the ear tuft developing later.
As with other members of the genus Callithrix, the common marmosets have claw-like nails known as tegulae on most of their fingers. Only their halluces (big toes) have the flat nails or ungulae that most other primates have. Marmosets have an arboreal locomotion similar to squirrels. They can hang onto trees vertically and leap between them, and run across branches quadrupedally. Tegulae are an adaptation for this type of locomotion. Other Callithrix traits shared include enlarged, chisel-shaped incisors and ceca specialized for their diet. Marmosets can be found in a number of forest habitats. They live in Atlantic coastal forests as well as semideciduous forests farther inland. They can also inhabit savanna forests and riverine forests. Marmosets are successful in dry secondary forests and edge habitats. The marmoset then licks up the exudates or swoops them with the teeth. From 20 to 70% of the marmoset's feeding behavior includes eating exudates. A marmoset group can contain as many as 15 members, but a more typical number is nine. Within the family groups, the breeding individuals tend to be more dominant. The breeding male and female tend to share dominance. Between two breeding females, though, one is more dominant. In addition, the subordinate female is usually the daughter of the dominant one. For the other members, social rank is based on age. Mating with extra-group males may allow the female to find potential mates in the future. Females that mate successfully but lose their young move to other groups and may gain dominant breeding positions. In addition, the presence of a related male affects female ovulation. Female ovulation does not occur when their fathers are around, but does occur when an unrelated male is nearby, instead. They also display aggressive behavior towards their mothers, In the following weeks, the young spend less time on their mother's back and more time moving around and playing. Marmosets also employ "phees", which are whistle-like, generic calls. These serve to attract mates, keep groups together, defend territories, and locate missing group members. Marmosets were recently found to encode the identity of the receiver in their phee calls — a behavior similar to the human use of names, and one that has been observed in only a few species: humans, dolphins, and African elephants. Marmosets use scent glands on their chests and anogenital regions to mark objects. These are meant to communicate social and reproductive status. In addition, marmosets are captured and traded as pets. Though popular as pets, they become difficult to control as they get older and may be abandoned or killed. Common marmosets have also been used for medical experiments. They are used as such in Europe more so than in the United States, and are the most common nonhuman primates to be experimented on. They are used as model organisms in areas of research such as teratology, periodontal disease, reproduction, immunology, endocrinology, obesity, and aging.
Genome
In 2014, a female became the first nonhuman primate, among the New World monkeys, to have its complete genome sequenced. or chimpanzees (about 5%), but more than in orangutans (3.8%).
References
External links
- Common Marmoset Care
- View the Marmoset genome in Ensembl.