Marmosets are the smallest of the New World primates and are naturally found in North South America. They have forward facing eyes, claws instead of nails and their heads can rotate 180 degrees in either direction. There is several marmoset species that are kept captive in the USA they include the common marmoset, Black eared marmoset and Geoffreys marmoset. Tamarins are often confused with marms. Their size and weight are similar to marmosets but are in a different genera based on their physiological traits. Marmosets and tamarins both scent mark their territory in the wild and live in similar groups. Tamarins and marmosets are usually monogamous but research has shown that in large family groups only one female actively reproduces, even breeding with different males.