thumb|[[Gatun Lake, Panama]]
Geoffroy's tamarin (Saguinus geoffroyi), also known as the Panamanian, red-crested or rufous-naped tamarin, is a tamarin, a type of small monkey, found in Panama and Colombia. It is predominantly black and white, with a reddish nape. Diurnal, Geoffroy's tamarin spends most of its time in trees, but does come down to the ground occasionally. It lives in groups that most often number between three and five individuals, and generally include one or more adults of each sex. It eats a variety of foods, including insects, plant exudates, fruits and other plant parts. Insects and fruits account for the majority of its diet, but exudates are also important. But since its teeth are not adapted for gouging trees to get to the sap, it can only eat exudates when they are easily available.
Although a variety of reproductive methods are used, the most common is for a single adult female in the group to be reproductively active and to mate with multiple adult males in the group. After a gestation period of about 145 days, she gives birth to either a single infant or twins. Males contribute significantly to care of the infants. Sexual maturity is reached at about 2 years, and it can live up to 13 years. Geoffroy's tamarin is classified as being "near threatened" by the IUCN.
Taxonomy
Like the other tamarins and marmosets, Geoffroy's tamarin is a New World monkey classified within the family Callitrichidae. However, more recent research indicates that the two taxa differ sufficiently to be considered separate species. According to genetic analyses, the two species diverged approximately 1.2 million years ago.
Physical description
In common with other callitrichids (tamarins and marmosets), Geoffroy's tamarin is a small monkey. With a length of between , excluding the tail,
Behavior
Like all callitrichids, Geoffroy's tamarin is diurnal and arboreal. This is normally done only in special circumstances, such as to acquire certain foods or to get to a tree it cannot otherwise reach. Groups often consist of more than one adult of each sex. Adults of both sexes migrate between groups.
Geoffroy's tamarin generally avoids sympatric small and medium size monkey species such as the white-headed capuchin and the Panamanian night monkey. Avoidance is spatial with respect to the capuchin, and temporal in the case of the night monkey, since Geoffroy's tamarin is only active during daylight hours and the Panamanian night monkey is only active at night. Geoffroy's tamarin is rarely observed in the vicinity of squirrels, although this appears to be the result of the squirrels avoiding interactions with the larger tamarins. Geoffroy's tamarin generally attempts to escape when birds of prey approach, regardless of whether the bird presents a true danger. However, the tamarins ignore one bird of prey, the double-toothed kite, which sometimes follows the tamarins in an apparent effort to feed on small animals disturbed by the tamarins. The gestation period is believed to be about 145 days, similar to the cottontop tamarin. It occurs in central and eastern Panama, with the range extending slightly west of the Panama Canal zone and has been observed as far west as Altos de Campana National Park. In Colombia, it occurs on the Pacific coast west of the Andes, south to the Rio San Juan.
Conservation status
The International Union for Conservation of Nature classifies Geoffroy's tamarin as being near threatened. Human activity in Panama can have both positive and negative effects on Geoffroy's-tamarin populations. While hunting decreases the population, cutting mature forest for agriculture provides more areas of secondary growth, which is beneficial for the tamarin.