Bottlenose dolphins are the most well-known type of dolphins. They live in seas all over the world except those around the Arctic and Antarctic Circles. They are 2-4 meters long and weigh between 150 and 650 kilograms. Although they are rather small among marine mammals, they are outstanding jumpers with great braking force. These master swimmers can swim approximately 45 kilometers per hour in short bursts. They are friendly and curious creatures who are thought to communicate among themselves by letting out various sounds or through body expressions.