Common Marmoset

11th June 2010

The common marmoset is one of two “minature monkeys” that can be seen in Birds of Eden's forest.

 

These monkeys are too small to live in the Monkeyland forest. They can therefore be found in the Special Monkey Home and inside Birds of Eden.

 

Strange but true: Did you know that these monkeys “tan”? The skin on their face changes colour in the sun!

 

Habitat: Common marmosets are found naturally in the northeatern and central forests of Brazil. They do well in dry secondary and disturbed forests as well as edge habitats, although they can live in other forest types such as savanna forest, riverine forest, coastal forest and semideciduous inland forest. C. jacchus are arboreal and quadrapedal. They also engage in leaping and vertical clinging. C. jacchus are exudativore-insectivores. This means that their primary diet consists of exudates like gum, sap, latex and resin as well as insects which provide protein and fat. common marmosets will also eat fruits, seeds, flowers, fungi, nectar, snails, lizards, tree frogs, nestlings and infant mammals.

 

Life history: Common marmoset females average 185 mm in length which is slightly longer than males who average 118 mm. The average weight of females is 236 g and males average 256 g. Gestation in C. jacchus is 143-153 days. Female C. jacchus can have 1-3 infants. Twins are often non-identical which is atypical for a primate. Female C. jacchus give birth twice a year. Infants are born without the characteristic white ear tufts that can be seen on adults. These develop with age. Twin infants can be up to 27% of the mother’s body weight when they are born. Infants are raised by the entire group, which takes some of this strain off of the mother. C. jacchus infants remain wth a caregiver constantly during the first 2 weeks of life. Infants are weaned around 3 months of age.  The juvenile period begins at 5 months and the sub-adult stage begins between 9 and 14 months. C. jacchus reach their adult weight at 15 months of age. At this time they are sexually mature. Adult C. jacchus are usually active for 11 or 12 hours a day between sunrise and sunset. C. jacchus sleep together as a group in trees as a precaution against predators like owls and snakes. C. jacchus have been observed to remain motionless for over 30 minutes while resting. The lifespan is 12 years in the wild.

 

Social structure: Common marmosets are found in groups of 3-15 individuals. Groups are stable and consist of an extended family unit. Within each group there are a few dominant breeders. The hierarchy for the remaining non-breeding individuals is deteremined by age, with gender being irrelevant. The females in a group are related. Males emigrate from their natal group when they reach adulthood. The group will separate if one of the breeders dies.

 

Communication: Common marmosets use expressions, postures, vocalizations and olfaction to communicate. A “partial open mouth stare” signifes alarm whereas a “slit-stare” conveys submission. These marmosets will flatten the ear tufts to signify also significy fear or submission.

Vocalizations include alarm calls and general calls. Two types of alarm calls are “staccatos” (given to sudden movements) and “tsiks”. “Phee” calls are used for long-range contact, mate attraction, and territory defense among other contexts. “Phee” calls resemble whistles.  Another type of general call is the “trill” which is used primarlty to identify conspecifics. “Trill” calls have a vibrato quality. C. jacchus have what has been termed a “second nose” to aid in olfactory communication called the vomeronasal organ. C. jacchus have scent glands on the chest and in the anogenital region. C. jacchus mark their territory with these scent glands. Smells are also used to denote social and reproductive status.

 

Matings: This is largely monogamous but polygyny and polyandry have also been observed. Mating patterns can vary over time. Mating is largely determined by suitable social conditions. Female C. jacchus flick their tongues at males to attract a mate. C. jacchus females can mate at any time of their 28-day cycle. However, the majority of mating occurs around the time of ovulation. Mating does not occur in C. jacchus unless the enviroment is suitable.

Other behaviours: These marmosets have special physical adaptions for their diets and eating methods. Instead of flat nails like other primates, C. jacchus has claw-like nails called tegulae that allows for locomotion resembling that of a squirrel. A portion of their large intestine called the cecum is also specialized. Finally, C. jacchus has incisors that are just as long as their canines. This allows gums and other exudates to be easily harvested.  

 

Conservation: C. jacchus is classified as lower risk/least concern by IUCN. This means that there is currently a viable population in the wild and although some habitat loss is occuring, threats to this species have not reached a critical point yet. As much as 80% of the natural range of C. jacchus has been razed for agriculture. C. jacchus is also commonly captured and sold into the pet trade. When primates become pets, they often are fed junk food and sweets and do not get proper nutrition. A common complaint heard from owners of C. jacchus is that they urinate on everything. This behavior is natural for C. jacchus but very undesirable in a pet. In addition to being a popular pet, C. jacchus is the most widely-used non-human primate in research in Europe. Brazil banned the export of C. jacchus in 1974. No C. jacchus used in biomedical research has come from the wild since this time. C. jacchus has been used to study immunology, obesity and aging among other areas.

 

Did You Know?  During resting, common marmosets are capable of remaining motionless for 30 minutes or more!

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