Cuttlefish have W-shaped pupils and can see polarized light, but are colorblind.

Some birds can sleep while flying.

Fact #332 · Animals

A polar bear’s sense of smell is extremely powerful.

Fact #486 · Animals

Some birds migrate between hemispheres each year.

Fact #203 · Animals

Some insects have compound eyes made of many lenses.

Fact #513 · Animals

Some insects undergo complete metamorphosis.

Fact #289 · Animals

Certain birds build hanging nests from woven plant fibers.

Fact #471 · Animals

A koala sleeps for many hours each day.

Fact #490 · Animals

A sea sponge is an animal, not a plant.

Fact #541 · Animals