Dolphin is a common name of aquatic mammals within the infraorder Cetacea. The term dolphin usually refers to the extant families Delphinidae, Platanistidae, Iniidae, and Pontoporiidae, and the extinct Lipotidae. There are 40 extant species named as dolphins.
Dolphins have 2 stomachs, one is used for storage of food and the other is used for digestion. They dive up to 1,000 feet Dolphins are known to be great divers. Being creatures of the sea, they can dive up to 1,000 feet underwater.
Even though the average lifespan of dolphins is about 17 years, some can even live up to 50 years!