The small pied tamarin is a resident in the Brazilian Amazon rainforest. It lives almost exclusively near the city of Manaus, the capital of Brazil's Amazonas state. Also known as the Brazilian bare-faced tamarin, it is distinctive with its bat-like ears and white and brown coat.

Unlike most monkeys, who have a male leader, the pied tamarins live in groups of around 15 individuals ruled by an alpha female. This social structure is very rare among primates, even among mammals. A more frequently mentioned example would be the hyenas that live on the savannas of Africa.

In a pied tamarin group, the alpha female is the only female that has the right to breed, as she produces pheromones to suppress other females' fertility. Both males and females in the group would help raise and take care of the children of the alpha.

Besides some cultural minorities with traditional polyandrous society, callitrichids are the only primates that practice polyandry. The term callitrichids refers to a group of monkeys that include tamarin, lion tamarin and marmoset. They are one of the smallest primates and usually weigh less than one kilogram. They're only primates who twin routinely. About 80 percent of births are twins. 

This rare species is listed as critically endangered by the IUCN Red List of Threatened Species and is one of the world's 25 most endangered primates. The drastic population decline is due to habitat loss caused by deforestation. Its population is still declining, as the city of Manus is continuously expanding and encroaching upon its habitat.

Primates in jeopardy

As the most common primate on Earth, homo sapiens share the same order with other 512 species across 93 countries. Non-human primates are our closest relatives on this planet. They play a significant role in various ecosystems, from the mysterious tropical forests to the grand African savannas. Their intelligence is fascinating and sheds light on studies of human society and behaviors.

However, many species of primates are on the brink of extinction. The series "Primates in jeopardy" is based on the list "World's 25 Most Endangered Primates (2018-2020)" co-published by IUCN SSC Primate Specialist Group (PSG), International Primatological Society (IPS), Global Wildlife Conservation (GWC) and Bristol Zoological Society (BZS).

This is the tenth iteration of a biennial listing of a consensus of the 25 primate species considered to be among the most endangered worldwide and the most in need of conservation measures.

(All photos via VCG. Cover image designed by CGTN's Chen Yuyang.)

(If you want to contribute and have specific expertise, please contact us at nature@cgtn.com)