Twenty years ago, you could find golden toads hopping through the rainforests of Costa Rica. But now they are all gone, killed off by a hot, dry spell in the 1980s.

Caribbean monk seals used to cruise the waters of Jamaica, Cuba, the Bahamas and beyond. They were overhunted, and the last one was seen in 1952

The Hawaii Oo bird was well known for its beautiful feathers. Several factors, including disease and habitat destruction, caused it to become extinct in the 1930s.

Passenger pigeons used to be common all over the United States. As farmers converted forests to farmland, they grew concerned that passenger pigeons would eat their crops. Consequently, the birds were hunted to extinction, and the last one died at the Cincinnati Zoo in 1914.

The Tecopa pupfish lived in the Mojave Desert in California. Development in the area led to its decline, and the Tecopa pupfish was declared extinct in 1981.