Dolphins.
Dolphins are highly intelligent mammals which can be found in seas and oceans. The common dolphin averages 2.4 m in length and 75 kg in weight.
Dolphins are carnivores, mostly eating fish, squid and crustaceans. Dolphins can be different in colour but generally they are grey with darker backs. Dolphins are well known for their agility and playful behavior, making them so much interesting and attractive to people. Dolphins live in social groups of five to several hundred. Dolphins produce an enormous variety of sounds, up to frequencies ten times those heard by human beings. Their aquatic natural enemies are sharks and killer whales. There are many reports of dolphins rescuing people from drowning.