Sea otters hold hands while sleeping to keep from drifting apart.

There's a species of jellyfish that is biologically immortal—it can revert to its juvenile form after maturing.

The shortest commercial flight in the world is less than two minutes long—it’s between the Scottish islands of Westray and Papa Westray.

A single strand of spider silk is thinner than a human hair but five times stronger than steel.

You can hear a blue whale's heartbeat from two miles away.

In Switzerland, it's illegal to own just one guinea pig because they are social animals and need companionship.

The word "nerd" was first coined by Dr. Seuss in his book If I Ran the Zoo.

There are more possible iterations of a game of chess than there are atoms in the known universe.

Honeybees can recognize human faces.

A duel between three people is called a "truel."