. Beginners' Zoology . Fig. 378. — Harpooning Greenland Whale(see Fig. 351). Po7poises and dolphins, which are smaller species ofwhales, live near the shore and eat fish. Explain the ex-pression blow like a porpoise. They do not exceed fiveor eight feet in length, while the deep-sea whales are fromthirty to seventy-five feet in length, being by far the largestanimals in the world. Tiie size of the elephant is limitedby the weight that the bones and muscles support andmove. The whales size is not so limited. The whale bears one young (rarely twins) at a mother carefully attends the you
. Beginners' Zoology . Fig. 378. — Harpooning Greenland Whale(see Fig. 351). Po7poises and dolphins, which are smaller species ofwhales, live near the shore and eat fish. Explain the ex-pression blow like a porpoise. They do not exceed fiveor eight feet in length, while the deep-sea whales are fromthirty to seventy-five feet in length, being by far the largestanimals in the world. Tiie size of the elephant is limitedby the weight that the bones and muscles support andmove. The whales size is not so limited. The whale bears one young (rarely twins) at a mother carefully attends the young for a long blubber, or thick layer of fat beneath the skin, servesto retain heat and to keep the body up to the usual tempera-ture of mammals in spite of the cold water. It also serves,along with the immense lungs, to give lightness to the body. MAMMALS 209. Why does a whale need large lungs ? The tail of a zvJiale is horizontal insteadof vertical, that it maysteer upward rapidlyfrom the depths whenneeding to teeth of someFig. whales do not cut the gum, but are reabsorbed and are replaced by horny platesof whalebone, which act as strainers. Give evidence,from the flippers, lungs, and other organs, that the whaleis descended from a land mammal (Fig. 397). Comparethe whale with a typical land mammal, as the dog, andenumerate the specializations of the whale for living inwater. What change took place in the general form of thebody .-• It is believed that on account of scarcity of foodthe land ancestors of the whale, hundreds of thousands ofyears ago, took to living upon fish, etc., and, gradually be-coming swimmers and divers, lost the power of locomotion on land. Order Why ? Elephants are rapidly becoming extinct because of thevalue of their ivory alsofurnish valua-ble products,but they willprobably
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