Dolphins are mammals, which means that they bare their young live, that they nurse their young, and that they breath air. In other words, they are not fish. There are a few other mammals that roam the sea, as well. Can you guess what they might be?

If one of your guesses was "whales" you would be correct. In fact, dolphins are related to whales. Whales are divided into two main groups - those that filter feed on plankton using baleen and those that grab their food, using teeth. Dolphins are grouped together with the second group of whales in a suborder called, Odontoceti - meaning "toothed whales". There are 70 species of "toothed whales", which include dolphins, porpoise, and whales.

The smallest Odontoceti is the species known as Commerson's Dolphin. It grows to just 5 feet long and only weights 65 pounds. The largest Odontoceti is the Blue Whale. This massive mammal is the largest animal ever thought to have lived on the planet and measures 100 feet and 150 tons.

Probably the best well known member of the Odontoceti suborder is the star of the movie, Free Willie - the Orca (more commonly known as the killer whale). An Orca can measure 23 feet and weigh 4 tons. They can reach speeds of up to 40 mph.

Porpoise are closely related to dolphins, but the shape of the nose and head and the coloration are sufficiently different to distinguish the two. Furthermore, the bottlenose dolphin is the only species of Odontoceti seen in this area.

The species of dolphin in Bull River and the one most often spotted on the East Coast is the Bottlenose Dolphin(Tursiops truncatus). It goes by several names: Grey Dolphin, Black Dolphin, Bottlenose Porpoise, Cowfish, Atlantic Bottlenose Dolphin, and Pacific Bottlenose Dolphin. This is the dolphin used in the TV show Flipper.