Frances Gum, age 15, of Hinton, West Virginia, for her question:

Does the hippopotamus sweat blood?

Sometimes the hippos thick hide becomes covered with a pinkish dew. He looks for all the world to be sweating blood, But actually, this is not so at all. The big fellow spends about half of his time in the water. Since he is a warm‑blooded, air‑breathing land animal, this calls for a special kind of skin. For, as you know, your skin objects if you keep it too long in the water.

The hippo's thick skin is fitted with special pores which protect it both in the water and. in the dry air. These pores give off an oily fluid which happens to be pinkish in color. After a few hours in the dry air, this pinkish oil oozes up to the surface of the skin. The hippo seems to be sweating blood.

Certainly this oily fluid prevents the hippo's hide from becoming dry in the air. Some experts believe that it is even more useful during the long hours spent in the water. The oil may protect the skin from the water, which tends to lick off the natural oils which keep the hippo's skin soft v and supple.

Apart from his pink so‑called sweat, the hippopotamus has other fascinating features, lie has the largest mouth of any land animal. What's more, he loves to open it wide just for you to admire. The monster teeth you see there are strong enough to snap a toothy, armor‑plated crocodile in two. This explains why the meaty hippo can share a river with hordes of hungry crocodiles and have no fear of being attacked.

He can swim against a strong current. He can walk on the bottom of the river. He can sink like a stone or rise like a cork as he chooses. Usually, he stays under water about two minutes. But, when necessary, he can hold his breath and stay under water for half an hour.

In spite of his looks, the hippo has a very pleasing character. Like most of the large animals of the world, he is a vegetarian. He does not look upon smaller animals as possible snacks. He is willing to live and let live. However, he refuses to be tormented and he makes short work of any meat‑hungry crocodile foolish enough to attack him.

The hippo's main food is water weeds, which he tears loose from the river bed. He prefers to spend his time between lazy sunbathing and ducking to find food, But sometimes he gets hungry for land plants. Then he may steal into a nearby truck garden at night and stuff himself on lettuce or other salad greens. This seems to be his only annoying habit,