Dolphins belong to the group of marine mammals.

Like all mammals they are warm-blooded, have some hair or fur (at some point of their lives), young are fed by the mother’s milk, breathe through lungs and develop in their mother’s womb (viviparous species)

Whales and dolphins are cetaceans, a group of marine mammals that spend their entire lives in the aquatic environment. However, 50 millions years ago their ancestors lived on land and, throughout all this time, they underwent several transformations that allow them to become well adapted to the marine environment.

Their limbs were modified into flippers, nostrils have “migrated” to the top of the head and fur covering their bodies was lost. They also gain a thick layer of blubber beneath the skin, which is now useful for maintaining their body temperature even in freezing cold waters. All these adaptations allow them a faster and most efficient swimming.

Within this amazing group, you can find a really wide variety of species, which can differ in size, habitats or physical characteristics.

One of the smallest species in the group is the Vaquita, with around 5 feet long and weighing ‘only’ 120 pounds. This is also the most endangered cetacean in the world today! The size record belongs to the Blue Whale, which can be 80 to 100 feet long and weigh up to 200 tons! It is the largest animal that ever inhabited the Planet!

Within cetaceans we find two different groups: the baleen whales (mysticeti) and the toothed whales (odontoceti).

How can you easily distinguish these two different groups? Find out here!