All dolphins, porpoises, and whales belong the scientific order called Cetacea.
There are two living sub-orders of cetaceans. The Mysticeti group contains the 13 baleen whales. These whales are generally very large. In fact, the enormous blue whale is the largest animal on earth! In their mouths, the Mysticetes have baleen strips hanging down from the upper jaw, instead of teeth. Baleen is a stiff structure with bristles that enables the whales to strain plankton and small fish from the water. Baleen whales have two blowholes, side-by-side, for breathing.

The Odontoceti group contain 69 species of  whales, dolphins, and porpoises with only one blowhole and teeth. Toothed whales eat a variety of fish, squid, and crustaceans. There is a great variation in the numbers and placement of teeth in different species of odontocetes. For example, the giant sperm whale has teeth only on the bottom jaw. The strange-looking strap-toothed beaked whale has only two teeth in its lower jaw that wrap up and over its upper jaw preventing it from opening its mouth very wide. The fabulous narwhal males usually have only one tooth, their left upper front tooth, that grows straight out in front to be a very long spiral tusk!

Dolphins and whales are mammals.
This means that they breathe air, nurse their young with milk, have hair, have a constant temperature, and give birth to live young.

 

Did you know?
Since both mom and calf
are swimming, nursing
requires coordination.
Dolphin babies make a
"taco" shape out of their tongue, insert it into
their mom's mammary slit,
then the mom squirts the
milk into their mouth!

Watch a dolphin
give birth!
Check out video footage of
the birth of a calf!

to watch.

Requires Quicktime.