"How do you say them? And which is which?"

That is what the very little boy asked about the rhinoceros and the hippopotamus when he came home from the London zoo. Their dreadful names made his head ache, and he couldn't tell them apart. He was sure children could have made up much better names for animals.

"Well, why is a dog a dog?"

"It isn't," said the very little boy; "it's a bow-wow." His papa laughed, for he was a very bright papa and saw the point. And then he told the very little boy that a great many things seemed to have been named, as a baby names a dog "bow-wow," by something about them that a child would notice first. Once upon a time, perhaps, a hunter in Africa or India, came upon two strange beasts. They both had enormous bodies on very short legs, and they both liked to wallow in the mud. When he went home he wanted to tell his friends about them so they would know the animals, too, if they ever saw them. One he called Mr. Nose Horn. That is, if he had been an Englishman, he would have said nose horn, but as he was a Greek, he said rhino-ceros, which means the same thing. The most striking things about the other animal was its huge horse-like face, and its habit of living most of the time and feeding in the water. So he called that animal hippo-pot-amus, two Greek words meaning river-horse.

No child could have made up simpler names than those. But, oh dear, when you come to study these queer animals it does seem that those wise old Greeks might have found better names. If they had thought of the shape of his body, his short legs, his rough, thick skin, of how he likes to wallow in a mud puddle and then go to sleep in the sun, of his four-hoofed toes, and of his sword tusks like those of wild boars in German forests, they would have called the hippopotamus the water-pig. And if those old Norsemen who used to roam over the northern seas in big row boats had seen the animal, these are the things they would have noticed: He can stay under water from five to eight minutes, he spouts when he comes up for air, his naked skin is oiled so he can slip through the water easily, and under that skin is a thick layer of solid fat. They would surely have thought the hippopotamus a land whale.

The hippopotamus has a body as long as the elephant's. It is from ten to fifteen feet around the middle, but the animal's thick legs are so short that he stands only five or six feet from the ground. Really his legs are better for swimming than for walking. He has the small, dull eyes of the pig sunk in folds of skin, small ears, a wrinkled, scowling forehead, a mouth two feet wide, and a bulging upper lip. He can use his sharp-edged tusks for rooting and for fighting, as the wild boar uses his tusks. He has a mustache of feeler hairs on his upper lip—like a cat? No, it is more like the bristles around the mouths of some whales—especially baby whales. But he doesn't breathe through holes in his head and spout water when he comes up to breathe, as the whale does. He has nostrils like other land animals. When he dives, he shuts his nose holes to keep out water, as the camel and giraffe shut theirs, to keep out sand.

Like other hoofed animals, the hippopotamus lives in herds and feeds on plants. From two to three dozen live together on the banks and in the beds of the warm rivers of Africa. They are not as bright as elephants, neither are they stupid. Not more than one or two of a herd are ever caught in the same kind of trap. Where hunters are about, the hippopotamus does not snort and blow when he comes up to breathe. Sometimes a herd leaves a place that is much hunted. They are rather timid and peaceable animals. When they hear a sound, or smell something they do not understand, they sink under water with only their noses above, and stand motionless, hidden among water plants. Maybe you have seen mud turtles do the same thing.

If attacked, a hippopotamus fights ferociously. A big bull hippopotamus will swim under a boat and tip it over, or bite a big piece out of the side, with his huge bark-cutting teeth. He chases the men in the water and gores them with his tusks. There are terrible "rogue," or tramp hippos, too, as there are among elephants.

A mother hippopotamus is the fiercest of all, if anything threatens her baby. She has only one at a time, and she makes it her chief business to look after him. He isn't born a swimmer, so for a long time he lives mostly on his mother's back. If caught young the baby hippopotamus is easily tamed, but he isn't bright enough to learn tricks. When his keeper comes to his cage he opens his two-foot wide mouth and begs for food in the most comical way. He asks for it much as a pig does. At home a herd of hippopotamuses at play shout with loud, harsh voices, but in a cage they creak and groan and squeal like very rusty hinges of a door.

When a herd of hippopotamuses in the Nile River becomes tired of a diet of water plants, they climb up higher and steeper banks than you could climb, break into fields and eat wheat and sugar cane. Just think of having a drove of animals in your corn field as big as elephants with their legs sawed off, with stomachs that hold five bushels, and with the table manners of pigs! Then, sometimes, they like to plaster their red and brown and gray-splotched, hairless bodies with mud, and go to sleep in the sun just like pigs. The only thing that will keep them out of a field is a bon-fire. Practically all wild animals are afraid of fire. That is a good thing to remember if you ever go camping in the woods or mountains.