Volume V Number 5 . . . . That Don't Fly. Review by Shannon Nesdoly. Millions of years ago, most birds flew in order to find food and escape from predators.
Predators are animals that hunt other animals.
Some birds, however, lived in places with few or no predators. There was plenty of food on the ground or in the water. These birds did not need to fly, so they flew less and less often. Over time, they lost their ability to fly and became flightless birds. Emus, ostriches, rheas, cassowaries and penguins may not be designed for flying, but their bodies have a variety of adaptations necessary for survival.