Monarch butterflies can migrate around 3,000 miles to spend the winter in Mexico.

Gutenberg's printing press, invented around 1440, made books much cheaper and helped more people learn to read.

Squirrels plant many new trees by burying acorns and nuts in the fall and forgetting where some of them are.

Cows have best friends and get stressed when they are apart.

A blue whale's heart is about the size of a bumper car.

Pigs are very smart and can learn their own names.

One day on Venus is longer than one year on Venus.