Since dolphins swim in the water many people think that they must be fish. However, dolphins are in fact warm-blooded mammals that breathe air and give birth to baby dolphins rather than lay eggs. This fact alone makes dolphins unique creatures, but they also have many more characteristics that make them one of the most interesting animals on the planet.

If you're ever had the opportunity to be near a dolphin you'll understand why they are as unique as they are. Dolphins, just like whales, are considered to be cetaceans and are part of the grouping of whales that are called odontocetes, which means that they have teeth. The teeth found on a dolphin are shaped like cones. Other whales fall into the group called mysticetes, in which case they don't have teeth to use for feeding.

You'll be able to find dolphins living in tropical, warm waters around the world. Unknown to most people is that there are a few species of dolphins that live in rivers and freshwater. These dolphins, however, are few in number and are now considered to be on the endangered list.

Almost 57 species of dolphins exist in the world. All dolphins have a lustrous body, which is very sleek. They have a typical long-beak like nose which is called the "rostrum". Very often, spectators tend to confuse between the porpoise and the dolphins. Both look similar in looks but are in fact different animals. The difference can be seen in their teeth. The porpoise have teeth shaped like spades for digging rocks, whereas the dolphins have teeth shaped like cones. One more main difference is that porpoises live in very cold water which cannot be tolerated by the dolphins.

The Orca or the killer whale is one of the most common species of dolphins. When people think of the most dominating and ferocious creature in the sea, the Orca or the Killer whale comes to everyone's mind. They are also the most fearless amongst all sea animals.

Dolphins have a long gestation period when it comes to the birth cycle of their young. The female dolphin will be pregnant for twelve months after which time she will give birth to one baby dolphin, called a "calf". Most baby calves will weight about 30 to 40 pounds and will be approximately 30 inches long. The mother dolphin will nurse her calf for the first two years of its life.

Young dolphins tend to stay close to their mothers for around five to seven years, which is a very long time when compared to other animals. In other animal species, the siblings leave the mother very soon after birth and are on their own. The young dolphins while staying with their mothers learn the nuances on how to pull on with the other dolphins and also how and where to look for their food.

Dolphins live and move around in groups known as "pod". The males stay detached and do not take any interest in parenting. It is the females who rear the siblings and do all the nursing. The female does all the interaction with the calves and males do not involve themselves in community life other than impregnating the females.

Dolphins are amazingly intelligent and curious. These traits make them intriguing to us, along with the fact that dolphins love to interact with humans. They are always ready to tell us all about what's going on in the waters around us, but unfortunately we aren't able to understand them.