Callithrlx jacchus (Common Marmoset) 
Utilization 
This small Brazilian primate has been used very little in the United 
States but is becoming valuable in Europe, and especially in Great 
Britain, for a number of research and testing purposes. Some of the 
most notable of these are reproductive physiology (including testing of 
antifertility products), teratology, toxicology, infectious diseases, 
drug safety, and a variety of behavioral studies. 
Since export of this animal from Brazil is currently prohibited, those 
being used in Europe come from domestic breeding programs which have 
proved to be practical and cost-effective. Only small numbers have been 
used in the United States; however, the potential of this species as an 
important animal model makes it imperative to consider it within the 
National Primate Plan. 
Foreign Sources 
The common marmoset is found in various forest formations in eastern 
Brazil. This animal is not available through normal trade channels 
because of export restrictions imposed by the Brazilian government. 
Production in United States 
Only one small general-purpose production colony of common marmosets is 
known to exist at this time. This colony, supported by a Public Health 
Service grant, is expected to produce between 100 to 150 animals per 
year. Special breeding programs are also limited and may, in fact, not 
exist. Even within the seven Regional Primate Research Centers, the 
major scientific resource for the study of primates as they relate to 
man, no production of this animal occurs, and the same is probably true 
throughout the United States. 
Recommendations 
Wliile there has been little breeding and use of this animal in the 
United States, recent experience in Europe indicates it is a valuable 
model for research and testing and that it is a highly cost-effective 
animal to breed in captivity. Its relatively short gestation period and 
frequency of twinning result in highly productive breeding colonies. 
This animal has the potential of becoming more generally useful because 
of its small size and ease of handling in the laboratory. It cannot be 
obtained through normal channels, and domestic breeding should be ini¬ 
tiated to produce a sufficient number to begin using them to meet new 
requirements for nonhuman primates in the United States. 
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