The golden lion monkey (Leontopithecus rosalia), one of the most threatened animals of Brazilian fauna, is still endangered, despite enormous efforts by various Brazilian and international organizations to restore the species.
Starting from the Atlantic Forest, in the state of Rio de Janeiro, a recent census carried out by the biologist Cecília Kierulff of the Federal University of Minas Gerais indicated the existence of only 559 monkeys of which just 290 were living in the Biological Reserve at Poços das Antas in the municipality of Silva Jardim (Rio de Janeiro). The others were found in areas without any protection where deforestation and hunting are not controlled.
In addition to this problem, the populations are very small and the isolation between them has resulted in considerable inbreeding which in some cases has reached 100%. Cecília Kierulff predicts that this fact, together with hunting and deforestation which have continued in the region, may lead to the non-viability of the species during the next hundred years.