The golden lion tamarin, one of the world’s most charismatic primates, has a dark face that can look inquisitive, challenging, almost human, framed in an extravagant russet mane.

The endangered New World monkey weighs less than two pounds. It lives only in Brazil, and only in the Atlantic coastal forest there. Tamarins spend their time high in the trees, up to 100 feet off the ground, in small groups of up to eight or so animals, with one breeding pair among each group.

They sleep at night and are active in the day, eating anything they can get their hands on — fruits, insects, small reptiles and amphibians. They have a life span of about eight years.

The golden lion tamarin has always had its human admirers, many of them in the Old World. Europeans imported the animals as pets in the 1500s, and they can be seen in portraits of Spanish royalty.