Dolphins are intensely social mammals that communicate with a variety of sounds including squeaks, whistles, and clicks. An echolocating bottlenose dolphin can make up to a thousand clicking noises per second.

Male dolphins are called "bulls", females "cows" and young dolphins are called "calves".

The largest dolphin species is the Orca, which is commonly known as the Killer Whale. These dolphins can be over 31 feet long when fully grown, a size which has earned them the colloquial name of whales although they are really dolphins.

Clocking in at speeds around 25 mph, this torpedo-shaped dolphin is among the sea's fastest swimmers, capable of jumping up to 20 feet in the air.

The baiji, or Chinese river dolphin, was native only to China's Yangtze River where it was regarded as the goddess of protection by local fishermen. The last known living baiji was Qiqi which died in 2002.

Nellie, a bottlenose dolphin who lived in a marine entertainment park in Florida, was born in 1953. She appeared on TV shows and commercials and performed tricks for the park's attendees before passing away in 2014 at the age of 61.