The dolphin is a mammal, though its physical appearance is very close from a fish. It has lungs and gives birth after a year of gestation. It is part of the cetacean family and lives either in the sea or in rivers.

Very fast, they can reach a speed of 37 mph thanks to their elongated figure, their very smooth skin and the strength of their movements. Dolphins can stay under water for 10 minutes. Their senses are very developed as well: they can see perfectly well in water and have no difficulty finding their way thanks to the ultrasounds they produce to 36 feet distance.
Dolphins live on little fishes that they crush with their very numerous and sharp teeth. Their most formidable predators are the killer whales and the sharks, but also men who pollute their natural spaces.

Dolphins have always been considered as man's friends. They were even regarded as gods in pre-hellelic Greece.
Friendship between man and dolphin is common. In Africa, dolphins help the fishermen to bring together shoals of fishes so they go straight to their fishing lines. Some even saved men from drowning by bringing them back up the surface! Some others are from now on famous all over the world, like Flipper from the TV-show, or Joséphine in Luc Besson's movie The Big Blue.
However, dolphins are also used by the American army to localize and get back some objects like some submarine mines. They were of a big help during the Vietnam war, as well as the Gulf war.