|World Book Encyclopedia, 1999 Edition. New York: Simon & Schuster, 1999.||"Killer whales and some smaller species of dolphins can swim at speed of 20 to 25 miles (32 to 40 kilometers) per hour."||9–11 m/s|
|Sarah's Dolphin Pages - Dolphin Facts. 1997.||"Did you know that some species of dolphin can swim at speeds up to 56 kmh [sic] (that's 35 mph, by the way). It's no wonder they can keep up with speeding boats!"||16 m/s|
|Simon and Schuster's Guide to Mammals. New York: Simon & Schuster, 1983||"It can swim up to speeds of 25 knots, and is often seen playing near ships."||11 m/s|
|Underwater World. New York: Time Life, 1992.||"By beating its tail up and down, this water dwelling mammal creates a strong thrust that enables it to swim 40 miles per hour."||18 m/s|
Dolphins are small aquatic mammals that are well-known for their grace and intelligence. They are much like whales, but have a well-defined beaklike snout. They are often called porpoises. Dolphins are spread all over the world in warm and temperate seas. Most dolphins are gray, blackish or brown above and pale below. Most grow to about 1 to 4 meters (3 to 13 feet) long. Most dolphins feed on fish, usually varying in number from a few to several hundred per day.
Dolphins can usually be seen swimming alongside and leaping near boats. They sometimes even try to swim along the wave created. These dolphins are usually seen in oceanarias. They have also been subject to scientific study for their intelligence and use of a range of sounds and ultrasonic pulses to communicate with its kind.
According to my research, dolphins can swim at up to speeds of about 10 to 20 m/s (20 to 40 mph). I reviewed encyclopedias, web sites on the internet, older reference books from the 1980s, and other books. The books all gave me about the same number for the speed of a dolphin.
Much to my disbelief, many dolphins can swim just just as fast or even faster than many boats. Also I was surprised that there were so many books and web sites on this topic. Doing this project was not as much trouble as I expected it to be.
Barrymore N. Joseph -- 2001