Steller’s sea cow: This giant, grazing mammal, a relative of manatees, was hunted to extinction by 1768.
Golden toad: The jewel-like golden toad lived in just one tiny patch of Costa Rican cloud forest. The last one was seen in 1989, and researchers think global warming, decreased rainfall or possibly a fungal infection caused its extinction.
Jamaica giant galliwasp: Introduced predators, such as mongooses, killed off this lizard species. It was last seen in 1840.
Dodo: Sailors who landed on Mauritius had eaten these flightless, docile — and, at least by reputation, dumb — birds to extinction by 1662.
Moa: Another flightless bird, these herbivores could grow to be 12 feet tall. They had been hunted to extinction by the 15th century.
Thylacine: Also known as a Tasmanian tiger, this street-dog-size animal had a stiff, catlike tail, a pouch on its belly and stripes on its back and rear that resembled a tiger’s. Hunting, invasive species and habitat loss led to its demise in 1936.