Dolphins sleep with only half of their brain and with one eye open so they can watch for predators and other threats.
Dolphin is a common name of aquatic mammals within the infraorder Cetacea. The term dolphin usually refers to the extant families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), and Pontoporiidae (the brackish dolphins), and the extinct Lipotidae (baiji or Chinese river dolphin). There are 40 extant species named as dolphins.
Although dolphins are widespread, most species prefer the warmer waters of the tropic zones, but some, like the right whale dolphin, prefer colder climates. Dolphins feed largely on fish and squid, but a few, like the killer whale, feed on large mammals, like seals. Male dolphins typically mate with multiple females every year, but females only mate every two to three years. Calves are typically born in the spring and summer months and females bear all the responsibility for raising them. Mothers of some species fast and nurse their young for a relatively long period of time. Dolphins produce a variety of vocalizations, usually in the form of clicks and whistles.
More fun facts about dolphins:
- Dolphins sleep with only half of their brain and with one eye open so they can watch for predators and other threats.
- Dolphins are known for their playful behavior, they are highly intelligent.
- Dolphins are part of the family of whales that includes orcas and pilot whales.
- Bottlenose dolphins are the most common and well-known type of dolphin.