The Greatest Mystery Of Whales
The whale is a warm-blooded,air-breathing animal,giving birth to its young alive,sucking them--and,like all mammals,originated on land.There are many front flippers(鳍状肢),used for steering and stability, are traces of feet.
__________ . (51)of this.Its Immense strength is __________ . (52)into the great body of the big whales,and in fact most of a whale’s body is one gigantic muscle.The blue whale’s pulling strength has been estimated __________ . (53)400 horsepower.One specimen was reported to have towed(拖)a whaling vessel for seven hours at the __________. (54) of eight knot (节).
An angry whale will __________ . (55) A famous example of this was the fate of Whaler Essex, __________ . (56)was sunk off the coast of South America early in the last century.More recently, steel ships have __________ . (57)their plates buckled(使弯曲)in the same way.Sperm whales(抹香鲸)were known to seize the old-time whaleboats in their jaws and crush Them.
The greatest __________ . (58)of whales is their diving ability.The sperm whale dives to the Bottom for his __________ . (59)food,the octopus(章鱼).In that search he is known to go as far Down as 3,200 feet, where the. __________ . (60)is 1,400 pounds,to a square inch.Doing so he
Will __________ . (61)underwater long as one hour.Two special skills are involved in this storing up enough __________. (62)(all whales are air—breathed)-and tolerating the great change in pressure.Just how he does it scientists have not __________ . (63).It is believed that some of the oxygen is stored in a special __________ . (64)of blood vessels,rather than just held in the lungs.And it is believed that a special kind of oil in his head is some sort of compensating mechanism that __________ . (65)adjusts the internal pressure of his body.But since you can’t bring a live whale