A dodo was a large, flightless bird that lived on the island of Mauritius in the Indian Ocean until it went extinct in the late 1600s. About the size of a turkey, with gray feathers, a big hooked beak, and stubby wings too small for flying, the dodo had no natural predators on its island home for a very long time. This meant it never needed to fly away from danger or fear humans.

When Dutch sailors arrived in the 1500s, they hunted dodos for food. Even worse, the rats, pigs, and monkeys that came with the ships ate dodo eggs, since the birds nested on the ground. Within about 80 years of human contact, every dodo was gone.

Today, we know the dodo mostly from a few scattered bones and old drawings. When someone calls an idea or invention “as dead as a dodo,” they mean it's completely obsolete and never coming back. The dodo has become a symbol of extinction itself: a reminder that once a species disappears, it's gone forever. Scientists have learned important lessons from the dodo's fate about protecting endangered animals before it's too late.