Groups of common dolphins, traveling and feeding together, may number up to 2000 individuals. Orcas, or killer whales, are actually the largest species of dolphin, though they feed on other dolphin species.
There are five species of freshwater dolphin living in Asian and South American rivers. Most catch fish by sound rather than sight.
Dolphins have been known to aid humans by keeping them afloat and driving off attacking sharks. Spinner dolphins are named for the acrobatic leaps they perform, spinning up to seven times in mid air.
The Atlantic hump-backed dolphin helps fishermen in West Africa by driving shoals of mullet into their nets.
In Mexico’s Baja California, bottle-nosed dolphins chase fish up onto the shore, then roll up onto the beach, completely out of the water, to grab them.
Military observers once recorded a group of dolphins swimming at 64 km/h in the bow wave of a warship.
The striped dolphin, seen in ancient Greek paintings, leaps up to 7 m to perform somersaults and spins.
The Yangtse dolphin, or baiji, is one of the world’s rarest mammals – probably less than 300 survive. V Many dolphin species `spy-hop’. holding their heads out of the water as they check on their surroundings for predators and potential food.
The Atlantic humpbacked dolphin inhabits mainly shallower waters, but is also known to swim close to fishing boats where it can feed on the rich shoals.