The golden lion tamarin is a squirrel-sized monkey found in southeastern coastal Brazil, in dense lowland rain forest. It is named for the mane of fur around its head and its bright coloration, which ranges from pale gold to a rich reddish-gold, with variable black markings, particularly on the tail.
The lion tamarins are the largest of the marmoset and tamarin group. More than 30 species of marmosets and tamarins are found in the Neotropics, from Panama through much of South America. Marmosets and tamarins differ from other monkeys in their small size and in having claws instead of flat nails on most of their digits (only the big toe has a flat nail). These claws help the small monkeys cling to trunks and branches.