Goeldi's marmoset

Goeldi's marmoset was first described in 1904, making Callimico one of the more recent monkey genera to be described. and sometimes, along with the marmosets and tamarins, in the subfamily Callitrichinae in the family Cebidae. Similarities in delayed embryonic development and secondary limb-bone ossification between C. goeldii and marmosets are evidence of their close evolutionary relationship. == Reproduction ==

Females reach sexual maturity at 8.5 months, males at 16.5 months. The gestation period lasts from 144 to 159 days. Callimicos studied in captivity in North America and Europe for near 40 years have shown to produce on average 3.5 offspring during their lifetime. However, 30% of the females and 45% of the males observed in these settings never reproduced. Unlike other New World monkeys, they have the capacity to give birth twice a year. The mother carries a single baby monkey per pregnancy, whereas most other species in the family Callitrichidae usually give birth to twins. These singleton births provide the offspring with longer maternal care and weaning delay that results in faster growth rates and in turn earlier sexual maturity than the other marmosets. == Infant care ==

For the first 2–3 weeks the mother acts as the primary caregiver after which the father and the helpers, who are often the siblings, share many of the responsibilities. However, mothers in the wild have been observed giving their babies to other members of the troop as early as 10 days after parturition, which is late for other marmosets. The life expectancy in captivity is about 10 years. == Development ==

From birth to about 18 months old, callimicos grow faster than other marmosets in part because the energy they would otherwise invest on thermal regulation and activity costs if they were not carried by their mothers is instead directed to growth. Likewise, a longer lactation period is also responsible for a faster development. Growth rate and weight gain is similar in both male and female infants and juveniles. == Distribution and habitat ==

Callimicos's geographic distribution extends from the Colombian Amazon and the Río Caquetá (Portuguese: Japurá) to the Peruvian and the western Brazilian Amazon, into the Pando department of northwestern Bolivia, where high densities have been reported. The distribution of the species is patchy, and its density seems to be dependent on polyspecific associations with tamarins. Sightings of Goeldi's marmosets have been made at the base of the Cordillera Oriental of the Andes in Colombia, in the Department of Putumayo, along the Putumayo and Caquetá Rivers. This is perhaps because Goeldi's marmosets are not known to have the X-linked polymorphism which enables some individuals of other New World monkey species to see in full tri-chromatic vision. ==Gallery==

File:Goeldis monkey - butterfly lunch - big.jpg|Marmoset eating a butterfly File:Callimico goeldii in Venezuela.jpg|Marmoset in Venezuela File:Callimico goeldii, Universeum.ogv|Callimico goeldii at Universeum, Gothenburg, Sweden ==References==