Bottlenose dolphin

The sea's cleverest, most playful creature

A dolphin is not a fish — it's a mammal and breathes air like we do! When it sleeps, half its brain stays awake — so it doesn't forget to breathe. Dolphins call each other by name — each has its own whistle. They love to play, and there are many stories of dolphins rescuing people.

The bottlenose dolphin (Tursiops truncatus) is the best-known dolphin, living in all warm and temperate seas. Its brain is larger than a human's, with a complex social life: groups of 10–30 that hunt together. Echolocation: through the 'melon' on its forehead it sends ultrasound and 'sees' a fish 100 m away from the echo — even its insides. Each dolphin has a unique 'signature whistle' — a name. Unihemispheric sleep: the halves of its brain rest in turn. It uses tools (protecting its snout with a sponge) and teaches this to its calves — a sign of culture.

Fun facts

• Dolphins call each other by name — a special whistle.
• When a dolphin sleeps, half its brain stays awake.
• Dolphins recognise themselves in a mirror — very few animals can.