What is the rarest species of bear?

The rarest bear species is the Sunda clouded leopard (Neofelis diardi). It is a medium-sized cat of the Felidae family native to the forests of Southeast Asia. The Sunda clouded leopard is listed as Vulnerable on the IUCN Red List, and its population is estimated to be less than 10,000 individuals. The main threats to the Sunda clouded leopard are habitat loss and hunting.