Behaviour

Tail wagging is a form of communication; the direction, speed, and height of the wag convey different emotions.

Cats knead as a comforting behaviour carried over from kittenhood, when they kneaded their mother while nursing to stimulate milk flow.

Ants follow scent trails of pheromones laid by nestmates, and busy routes get reinforced until a neat line forms along the best path.

Squirrels bury nuts to store food for winter. Many buried nuts are never recovered, which helps new trees grow.

Sea otters often hold paws or wrap themselves in kelp while sleeping on the water so they don't drift apart from their group.

Roosters have an internal body clock that makes them crow just before dawn, even without seeing light. The top-ranking rooster usually crows first.