There were once 9 subspecies of tigers: Bengal, Siberian, Indochinese, South Chinese, Sumatran, Malayan, Caspian, Javan and Bali. The last 3 are extinct, one is extinct in the wild, and the rest are endangered.

In 1956, a scientist imported African honeybees to South America. Some of them escaped and bred with European honeybees in the wild, giving rise to a hybrid species: killer bees.