Golden lion tamarin

Zoos bred these small orange monkeys with one aim: to send them home to Brazil's Atlantic Forest. On May 31, 1984, a family of eight zoo-born tamarins was released in Rio de Janeiro state, and over the next 16 years a total of 146 captive-born tamarins followed. It worked. A 2024 census counted 4,800 in the wild, more than 2,500 of them descendants of those released animals, and the species was moved from Critically Endangered to Endangered in 2003. The 2017 yellow fever outbreak showed how quickly disease can cut into those numbers, and illegal trafficking in the animals is still a threat.