The passenger pigeon — once the most numerous bird in North America — went extinct in 1914 due to hunting.

Some birds can sleep while flying.

Fact #332 · Animals

Some insects undergo complete metamorphosis.

Fact #289 · Animals

Many species of beetles have hardened wing covers called elytra.

Fact #457 · Animals

The largest known dinosaur species were long-necked sauropods.

Fact #630 · Animals

A cheetah can accelerate from 0 to 60 mph in a few seconds.

Fact #363 · Animals

A crocodile can replace its teeth multiple times in its life.

Fact #406 · Animals

The first dinosaurs appeared during the Triassic period.

Fact #632 · Animals

Some ants can carry many times their own body weight.

Fact #132 · Animals