Dolphins are warm-blooded marine mammals that breathe air through a blowhole, or nostril, that is located at the top of their heads. The nearly 40 species of dolphins vary in size and appearance, with some characterized by their blunt, rounded heads, while others, such as bottlenose dolphins, having elongated jaws that form a beak. The above bottlenose dolphin was caught on film as it swam after a research boat in Florida's Banana River, near the Kennedy Space Center.
Commerson's dolphins (Cephalorhynchus commersonii) are easily identified by the distinctive black and white patterns on their bodies. Because of their appearance, they are also known as skunk dolphins, piebald dolphins and panda dolphins. Commerson's dolphins are found in several inlets in Argentina and near the Kerguelen Islands. [View: World's Cutest Sea Creatures]
The sun casts ripples from the surface onto a pair of Atlantic spotted dolphin (Stenella frontalis) in crystal clear Bahamian waters. These dolphins are found in the Gulf Stream of the North Atlantic Ocean. True to their names, the dolphins are a dark gray color and have white spots on their flanks.
The bottlenose dolphin (Tursiops truncates) is one of the most well-known dolphins, and is often referred to as "Flipper" because of the TV series. Bottlenose dolphins have a worldwide distribution through tropical and temperate waters and can frequently be spotted along the shores of the United States.
The Guianadolphin (Sotalia guianensis) lives in the waters off eastern South and Central America and the Caribbean. It looks like a smaller bottlenose dolphin, with a steel blue to chocolate brown body with a white or pale pink belly. The above Guiana dolphin gets a treat for participating in a research project.
Researchers have recently discovered that common Guiana dolphins possess the ability to sense electric fields, making them the first placental mammals known to pull off this trick. Researchers believe that the dolphins most likely use this sixth sense to find prey in the murky coastal waters they inhabits. This Guiana dolphinis leaping out of the water.
Spinner dolphins (Stenella longirostris) are found in off-shore tropical waters around the world. As fun-loving as they are intelligent, dolphins enjoy playing games and performing acrobatic stunts. Above are mating spinner dolphins in Sataya, Southern Red Sea, Egypt.
Striped dolphins (Stenella coeruleoalba) are named for the characteristic blue and white stripes running along their flanks. They are among some of the most widespread and abundant dolphins in the world.
This young albino bottlenose dolphin was observed in June 2007 in Calcasieu Lake, La., which is located just east of the Texas-Louisiana border. The calf was swimming with its mother, who is not albino. Albinism is a recessive gene, so two non-albino parents that are both carriers of the albino gene have a 25-percent chance of having an albino baby.
Found in the cool to temperate waters of the North Pacific Ocean, the Pacific white-sided Dolphin (Lagenorhynchus obliquidens) is extremely active and a fast swimmer that loves to perform acrobatic moves such as turning somersaults in the air. It has a distinctive white, dark gray and light gray pattern on its body, with a two-toned dorsal fin that becomes a lighter gray shade toward the back.
The dusky dolphin (Lagenorhynchus obscurus) is very closely genetically related to the Pacific white-sided dolphin, but the two have been identified as separate species. It is also has a two-tone dorsal fin, is highly active and enjoys performing acrobatics, including leaping out of the water and belly-flopping.
The Yangtze River dolphin (Lipotes vexillifer), or baiji, are a type of freshwater dolphin thought to be the first dolphin species driven to extinction due to the impact of humans. The above male Yangtze River dolphin, named "Qi Qi," was held at the Wuhan dolphinarium from 1980 to 2002.
Two Clymene dolphins (Stenella clymene) leaping from the water. Clymene dolphins are native to the Atlantic Ocean and prefer temperate and tropical waters. They grow to about to about 6 feet 7 inches (2 meters) in length are slightly shorter than their Spinner dolphin relatives.
Also known as the Grampus, Risso's Dolphin (Grampus griseus) has a rounded head and extensive white scarring that occurs naturally as a result of parasites or scratches and bites from other animals. The above dolphin was spotted near a boat 30 miles out at Avila Beach, Calif.
The short-beaked common dolphin (Delphinus delphis) is, well, pretty common. There are more short-beaked common dolphins than any other dolphin species in the warm-temperate portions of the Atlantic and Pacific Oceans. They are fast swimmers, enjoy aerial acrobatics and can sometimes be seen swimming closely alongside boats, a behavior known as "bow riding."
Bottlenose dolphins tend to live in "pods" of 10 to 30 members, although group sizes can vary. They often hunt in groups and communicate using a special language of squeaky sounds emitted from their blowholes. They also communicate through body language, such as slapping the water's surface with their tails, which are called flukes.
The hourglass dolphin (Lagenorhynchus cruciger) is rarely spotted in the wild. To date, only about 20 partial or complete hourglass dolphin specimens have been examined and recorded. The dolphins get their names from the white bands that run lengthwise along their bodies in a somewhat hourglass shape. Because of its black and white colors, it is also sometimes referred to as a "sea cow."
The Amazon river dolphin (Inia geoffrensis) is a freshwater river dolphin that is not only found in the Amazon River, but also in the Orinoco River, as well as the Araguaia/Tocantins River systems of Brazil, Bolivia, Peru, Ecuador, Colombia and Venezuela. Scottish researchers learned that male Amazon river dolphins sometimes carry natural objects, such as sticks and rocks, in their beaks, then throw them or thrash them against the water's surface, possibly to impress females.
New Research shows that the babies of cetacea, an order of marine mammals that includes dolphins, whales and porpoises, stay awake for over a month after they are born. This finding challenges the idea that growing babies need rest. The above bottlenose dolphin calf swims alongside its mother.
Hector's dolphin (Cephalorhynchus hectori) is found only in New Zealand. It is named after Sir James Hector, a Scottish scientist who studied the first found specimen of the dolphin in 1881. At about 4.5 feet (1.4 meters) in length, the rare dolphin is one of the smallest cetaceans.