Common Marmoset (Callithrix jacchus)
Common Marmoset (Callithrix jacchus) is a New World monkey. It originally lived
on the Northeastern coast of Brazil, in the states of Piaui, Paraiba, Ceará,
Pernambuco, Alagoas and Bahia.[4] 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) and became there 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.[5]
Description
The fur of the Common Marmoset is grey. The most distinguishing characteristic
is the white tufts of hair which surround the ears, which lend it another common
name, the Cotton Eared Marmoset. A white mark is on the forehead and the face is
hairless. The long tail is grey-white. Common Marmoset adult size ranges from 14
cm (5.5 in) to 18 cm (7.1 in) and they weigh approximately 400 g (14 oz).
Habitat
Like all callitrichines, the Common Marmoset is diurnal. Its habitat ranges from
the edge of forests into the deep forests, but it also appears in fields. It can
run swiftly along the branches of trees and is also an excellent jumper. In its
introduced range, can be found within cities, being common in Rio de Janeiro; is
also found in Buenos Aires[6].
Diet
The diet of the Common Marmoset consists of insects, spiders, small vertebrates,
bird eggs and tree sap. They spends 25-30% of their time budget searching for
food.
Behavior and reproduction
Common Marmosets live together in family groups of four to 15 animals, usually
mated adults and their offspring. These groups inhabit territories of 300,000 m2
(74 acres). The groups have a strict ranking, ordered by the dominance and
aggressive behavior of the group leader.
Common Marmosets have variable mating systems: monogamous, polygynous and
polyandrous. All adults and subadults share in the care of the young. After an
approximately 150-day gestation, the female typically gives birth to twins,
though up to four offspring have been observed in captive settings (larger
litters suffer higher mortality rates). Compared to adults, the young animals
are very large. Newborn twins together are 20 percent to 27 percent of the body
weight of the mother, and it is assumed that the cooperative care of young helps
counter some of the high costs of raising twin offspring. Males can mate after
about one year, while females aren't fully mature until about 20 to 24 months.
Lifespan
The life expectancy of the Common Marmoset in the wild is about 10 years,
although some living in captivity have lived to 16 years.