You will never see the great auk, the laughing owl or the O'ahu 'O'o at the zoo or even in the wild because these species are gone forever. That's extinction—when all the members of a species have died. Once a species becomes extinct, our planet changes forever.

Extinction is a natural part of our Earth’s history, but today species are becoming extinct faster than ever. Every year, new species are becoming threatened with extinction. The biggest threats to our planet’s species are humans. Our world’s population is increasing by millions each year. All these people are using more and more resources, leaving fewer resources for Earth’s other species.