Poço das Antas Biological Reserve, Biological reserve in Silva Jardim, Rio de Janeiro, Brazil.

Poço das Antas Biological Reserve covers 5,052 hectares of Atlantic Forest in the municipality of Silva Jardim, Rio de Janeiro. Its terrain is relatively flat, rising from 14 to 205 metres, and the São João River marks its boundary. Dense lowland rainforest, partly flooded, covers about half the area, crossed by small springs, channels and streams.

The area was established in 1974 as a major step forward in forest protection within Brazil. This founding demonstrated government commitment to safeguarding threatened ecosystems at a critical moment.

The golden lion tamarin, symbol of the Atlantic Forest, owes its survival to primatologist Adelmar Coimbra Filho and environmentalist Alceo Magnanini, whose work led to the reserve's creation in 1974. The reserve keeps the largest population of the species, with just over 560 individuals. The Golden Lion Tamarin Conservation Project continues efforts to save it from extinction.

The main entrance is located on a federal highway north of Rio de Janeiro, making it accessible by car. Paths through forest areas require sturdy shoes and preparation for outdoor conditions, so plan accordingly for your visit.

This location holds the world's largest wild population of the golden lion tamarin, with hundreds living there and being studied by researchers. The species is so rare and fragile that its survival depends greatly on this reserve and ongoing conservation work.