Reproduction
Females reach sexual maturity at about 8.5 months, males at 16.5 months. Gestation period averages 155 days (range 139-180 days). Females give birth to one infant at a time with infants being weaned by 65 days.

Life Cycle
Infants are cared for solely by the mother for the first 10-20 days of life, then the group members share in the carrying. Not a lot is known about the social structure of wild Goeldi's, but studies indicate that there may be various forms, including monogamy, one breeding pair per group, multi-breeding pairs and one male with more than one breeding female. Average group size is six members with group bonds being very strong. Members remain within 50 feet (15 m) of each other and maintain contact by a shrill call.

About 40 different vocalizations have been noted, including a trill for alarm and warning. Goeldi's rest separately rather than in close contact with each other, except during their midday rest, when they groom one another.

Missing Link
While the Goeldi's monkey was first described by zoologist E.A. Goeldi in 1904, it was not exhibited in a North American zoo until 1955. They are very significant due to skeletal features (mainly the skull) which resemble Asian and African monkeys. The Goeldi's monkey may represent a link between the two major primate families.

Low to the Ground
Goeldi's monkeys prefer to travel and forage below 16 feet (5 m) but do feed in the tops of fruit trees as high as 100 feet (30 m). If disturbed, they will stay below 16 feet (5 m) to flee and hide. If surprised, it is reported that a Goeldi's monkey will park its infant on a branch and escape.

Visitors can view the zoo's Goeldi's monkeys at their exhibit in the Tropical Rain Forest. Be patient, look closely, they may be hiding in the exhibit's thick foliage. Sharing the exhibit with the Goeldi's monkeys are pygmy marmosets, the world's smallest monkey. Look for these small animals among the exhibit's branches.

How You Can Help!
The effort to save endangered species requires cooperation and support at the international, national, regional and individual levels. You can help in this cause. Join and become active in Woodland Park Zoo and other conservation organizations of your choice. Please do not buy products made from wild animal parts. Contact your elected representatives and express your views about conservation of endangered species and wild habitats.

Contact Woodland Park Zoo at webkeeper@zoo.org to find out ways you can support conservation programs at the zoo. Learn other ways you can help conserve wildlife and the habitats they require for survival by visiting our How You Can Help page.

Sources and Suggested Reading
Coimbra-Filho, Adelmar F. and R.A. Mittermeier. 1981. Ecology and Behavior of Neotropical Primates, Goeldi's Monkey, Genus Callimico. Chapter 4: pp. 169-209.

Macdonald, David, ed. 1993. The Encyclopedia of Mammals. Facts on File, Inc., New York, NY. 895 p.

Nowak, Ronald M., ed. 1991. Walker's Mammals of the World. 5th Edition. The John Hopkins University Press, Baltimore and London. 1,629 p.

Rowe, Noel. 1996. The Pictorial Guide to the Living Primates. Pogonias Press, East Hampton, New York, NY. 263 p.

For Kids!
Julivert, Maria Angels. 1996. Primates. Barron's Educational Series, Inc., Hauppauge, New York, NY. 31 p.

More References

* Taxonomic classification varies between references. Classification information used in this fact sheet was taken from Mammal Species of the World: A Taxonomic And Geographic Reference, edited by Don E. Wilson and Dee Ann M. Reeder, Second Edition, 1993.

**Woodland Park Zoo identifies an animal or plant endangered if it is listed as endangered (in any part of its range) on the federal list of Endangered and Threatened Species, or if is listed on Appendix 1 of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).