The word 'nerd' first appeared in a Dr. Seuss book in 1950 — 'If I Ran the Zoo.'

Some birds have hollow bones to reduce body weight for flight.

Fact #889 · Human Body

The human brain weighs about three pounds on average.

Fact #244 · Human Body

A narwhal’s tusk is actually an elongated tooth.

Fact #551 · Human Body

Camels have specialized red blood cells that help them survive dehydration.

Fact #856 · Human Body

Humans reached the Moon less than 70 years after powered flight.

Fact #1741 · Human Body

Polar bears have black skin beneath their white fur.

Fact #26 · Human Body

The human brain contains roughly 86 billion neurons.

Fact #8 · Human Body

The axolotl can regenerate limbs and even parts of its heart.

Fact #366 · Human Body