Changes

Dolphins are streamlined for a life in the water; the body is cigar-shaped and tapered towards the tail, bearing a smooth, hairless skin which has a “rubbery” feel to the touch.  The forehead bears a large, bulbous mass called a “melon”, which is thought to be the area where sound waves are focused when the animal echolocates or communicates with others.  Behind the melon on top of its head is a single blowhole through which it breathes when it comes to the surface.

Dolphins are streamlined for a life in the water; the body is cigar-shaped and tapered towards the tail, bearing a smooth, hairless skin which has a “rubbery” feel to the touch.  The forehead bears a large, bulbous mass called a “melon”, which is thought to be the area where sound waves are focused when the animal echolocates or communicates with others.  Behind the melon on top of its head is a single blowhole through which it breathes when it comes to the surface.

Dolphins have a pair of pectoral fins behind the head, which they use for steering.  Primary propultion comes from the tail, which bears horizontal flukes made from subcutaneous dermal tissue; movement through the water consists of vertical sweeps of the tail.  Speeds of dolphins have been estimated at  23-25 mph (37-40 km/h), which is enough to allow for “porpoising” i.e. the leaping of the animal out of the water at various times.  Some species have been observed to reach higher speeds.

Dolphins have a pair of pectoral fins behind the head, which they use for steering.  Primary propultion comes from the tail, which bears horizontal flukes made from subcutaneous dermal tissue; movement through the water consists of vertical sweeps of the tail.  Speeds of dolphins have been estimated at  23-25 mph (37–40 km/h), which is enough to allow for “porpoising” i.e. the leaping of the animal out of the water at various times.  Some species have been observed to reach higher speeds.

Most species of dolphins also bear a dorsal fin on their backs, made from the same dermal tissue as the tail flukes, and is believed to act as a stabilizer while moving.  In some species (orca, grampus), the dorsal fin is rather large relative to the size of the body; in several others the fin is a small ridge extending over a portion of the back (river dolphins), or entirely non-existant (right whale dolphin).

Most species of dolphins also bear a dorsal fin on their backs, made from the same dermal tissue as the tail flukes, and is believed to act as a stabilizer while moving.  In some species (orca, grampus), the dorsal fin is rather large relative to the size of the body; in several others the fin is a small ridge extending over a portion of the back (river dolphins), or entirely non-existant (right whale dolphin).

==Range==

==Range==

Dolphins are found in nearly all oceans and seas of the world, from tropical environments to arctic conditions.  Most species are pelagic (deep ocean), and some inhabit continental shelves towards the coast.  There are four species of river dolphin; two inhabit the freshwater rivers of South America<ref>http://www.acsonline.org/factpack/Boto.htm</ref>, one in India, and the fourth – which may in fact be extinct<ref>http://news.nationalgeographic.com/news/2006/12/061214-dolphin-extinct.html</ref> – lives in China.

Dolphins are found in nearly all oceans and seas of the world, from tropical environments to arctic conditions.  Most species are pelagic (deep ocean), and some inhabit continental shelves towards the coast.  There are four species of river dolphin; two inhabit the freshwater rivers of South America,<ref>http://www.acsonline.org/factpack/Boto.htm</ref> one in India, and the fourth – which may in fact be extinct<ref>http://news.nationalgeographic.com/news/2006/12/061214-dolphin-extinct.html</ref> – lives in China.

==Diet==

==Diet==