Dolphin (aquatic mammal)
I INTRODUCTION
Dolphin (aquatic mammal), fast-swimming animal related to whales and porpoises. Sleek and powerful swimmers found in all seas, dolphins are distinguished from porpoises by well-defined, beaklike snouts and conical teeth. The porpoise has a blunt snout, chisel-shaped teeth, and a stouter body.
There are at least 32 species of dolphins. Typical examples are the bottle-nosed dolphin, a popular performer in seaquariums, and the mon dolphin, which inspired many Mediterranean folk legends. Both often appear in open waters, making their characteristic arched bounds, frequently before the bow waves of ships. Several freshwater species inha**t river estuaries in Asia and South America. The **all, graceful tucuxi dolphin has been sighted more than 2000 km (more than 1250 mi) up the Amazon River. The tucuxi, the **allest dolphin, is less than 1.2 m (less than 4 ft) long; the largest, the bottle-nosed dolphin, reaches a length of 3 m (10 ft). The killer whale is considered a dolphin despite its much greater length of 9 m (30 ft).
Dolphins once were hunted mercially, especially for the **all quantity of valuable oil extracted from parts of the head and used to lubricate delicate watch mechani**s. Cheaper oils have now been found from other sources, and dolphins are no longer hunted for this reason. Many dolphins, however, bee accidentally trapped and drowned in tuna nets; between 1959 and 1972 an estimated 4.8 million dolphins died in this way. Under pressure from animal rights activists and United States consumers, both domestic and international tuna canners have refused to accept shipments from fishing fleets that do not protect dolphins. Concern has also been expressed about the treatment of dolphins on display in public aquariums and in “swim with the dolphins” programs. The Marine Mammal Protection Act of 1972, amended in 1988 and 1992, was passed to prevent exploitation of dolphins and related aquatic animals.
Dolphin, bodily form looks like the fish, the mouth is thin and long, upper and lower jaws have 46- 6 sharp and thin teeth respectively, the body is thin and long , generally about 2- 2. meters long. The back in the shape health of streamline, the dorsal fin with sickle form . The back is greyish black, the belly is white, the place close to head of belly has a pair of pectoral fins. The weight is between 100- 20 kilograms. Although its mouth is kissed long, there are so many teeth in the mouth, it can't chew the food , just consume **all fish , shrimp , cuttlefish ,etc.. Dolphin, bodily form looks like the fish, the mouth is thin and long, upper and lower jaws have 46- 6 sharp and thin teeth respectively, the body is thin and long , generally about 2- 2. meters long. The back in the shape health of streamline, the dorsal fin with sickle form . The back is greyish black, the belly is white, the place close to head of belly has a pair of pectoral fins. The weight is between 100- 20 kilograms. Although its mouth is kissed long, there are so many teeth in the mouth, it can't chew the food , just consume **all fish , shrimp , cuttlefish ,etc.. dolphins on display in public aquariums and in “swim with dolphins are no longer hunted less than 1.2 m (less than 4 ft) long; 你可以上这个空间看看。这里有好多资料
海豚的介绍海豚有着圆滑的流线型身体，以及具有推进作用的扁平尾巴。和所有的哺乳动物一样，它们用乳汁哺育幼仔。
快速游泳者：世界上有31种海豚，它们有鱼一样的体型、光滑的皮肤以及扁平的尾巴，凭此它们可以在游泳时间毫不费力地达到很快的速度。优秀海豚可以连续几小时保持每小时40km的速度
这种海豚是快速的游泳者，嘴里有160克小牙齿，以小鱼、鳗鲡和乌贼等为食。我不会~~~但还是要微笑~~~：）