Frequently dolphins will accompany boats, riding the bow waves. They are also famous for their willingness to occasionally approach humans and interact with them in the water. In return, in some cultures like in Ancient Greece they were treated with welcome; a ship spotting dolphins riding in their wake was considered a good omen for a smooth voyage.
Dolphins are social animals, living in so called schools of up to a dozen animals. In places with high abundance of food, schools can join temporarily forming aggregations of over 1000 dolphins. The individuals communicate using a variety of klicks, whistles and other vocalizations. They also use ultrasonic sounds for echolocation.
Membership in schools is not rigid, interchange is common. However, the animals can establish strong bonds between each other. This leads to them staying with injured or ill fellows for support.
更新1:
Dolphins are predators, chasing their prey at high speed. The dentition is adapted to the animals they hunt: Species with long beaks and many teeth forage on fish, whereas short beaks and lesser tooth count are linked to catching squid. Some dolphins may take crustaceans.
更新2:
Usually, the prey is swallowed as a whole. The bigger species are capable of eating marine mammals, especially the orca, which kills even large whales. Taxonmony Phylum: Chordata Class: Mammalia Order: Cetacea Family: Delphinidae
