Vaquita - There are fewer than 10 vaquitas left in the world, making it the most critically endangered marine mammal species.
Javan Rhino - With less than 60 individuals left in the wild, the Javan Rhino is one of the rarest large mammals on earth.
Sumatran Elephant - With less than 2,500 individuals left in the wild, the Sumatran elephant is one of the world's most endangered elephant species.
Amur Leopard - With less than 100 individuals left in the wild, the Amur Leopard is one of the rarest big cats in the world.
Saola - The saola, or the "Asian unicorn," is one of the rarest mammals in the world, with an estimated population of only a few hundred individuals.
Northern Hairy-Nosed Wombat - With fewer than 250 individuals left in the world, the northern hairy-nosed wombat is one of the rarest mammals in the world.
Red Wolf - With fewer than 20 individuals left in the wild, the red wolf is one of the rarest canids in the world.
Madagascar Pochard - With fewer than 25 individuals left in the wild, the Madagascar pochard is one of the rarest waterfowl species in the world.
Angel Shark - The angel shark is one of the rarest shark species in the world, with an estimated population of fewer than 1,000 individuals.
Golden Tabby Tiger - With only a handful of individuals in captivity, the golden tabby tiger is one of the rarest big cat variants in the world.