If you like to be surprised, all of a sudden, just stand by the kangaroo pen in a park zoo awhile. In fact, if you are lucky, you will be surprised twice.

You are sure to wonder, at first, why there is such a very high, strong fence of iron posts and netting around these queer-looking animals. No taller than kindergarten children, they sit upright as neatly as if on three-legged stools. You might say they are three-legged stools, for kangaroos rest on two hind legs and a long fat tail. From these broad bases their bodies taper up in the oddest way, to narrow, sloping shoulders and small, deer-like heads. Their full bright eyes glance about, their rabbit-like ears stand erect, listening. In front of the breast the short fore-paws are drooped, as if they are there less for use than for ornament.

Sometimes the kangaroo drops on all fours and eats like a rabbit, hopping about on his hind legs like a robin. But it seems to be easy for him to pick up a carrot, hold it between his paws and eat like a squirrel. The keeper knows what he is about when he scatters the food, putting some choice bits in the farthest corners of the pen. He does that so you can see the animals—jump!

There! You nearly jumped out of your skin, didn't you? That's surprise number one. When a kangaroo wants to go across his pen he doesn't waste time in hopping. He just stretches up on his hind legs and leaps. If a frog was as big he might jump farther than a kangaroo, but he couldn't jump as high. It really must have been the kangaroo, and not the cow, that jumped over the moon and made the little dog laugh.

No wonder the kangaroo can jump so far and so high. He has the biggest and strongest hind legs, for his size, of any animal in the world. His hind feet are so long it looks as if he were sitting on his hind elbows. At the end of the foot is the biggest big toe! It is in the middle of the foot, and has on it a long, sharp, wicked-looking, dagger-like claw. On one side of this big toe is a small one. On the other side a pair of helpless little twin toes dangle from the leg. The kangaroo's hind leg, foot and big toe are as wonderful, in their way, as the elephant's trunk.

A long, long time ago, when there were big, fur-covered elephants on the earth, there were also kangaroos as big as hippopotamuses, with heads three feet long. Perhaps it was these huge jumping beasts that started the story of the giant, who wore seven league boots and could step over small mountains. Why, a kangaroo six feet high of today can leap over a horse and rider, and then get away, by jumping as fast as the horse can run

These queer animals live in only one place in the world—the big island continent of Australia, away around on the other side of the earth. Living on grass, small plants and the roots of herbs, they take the place of the deer and antelopes of other countries. Like other grass-eating animals they live in herds with leaders, and are naturally very timid and peaceable. There are a dozen varieties of kangaroos. The largest are as tall as a man, and weigh one hundred and fifty pounds. The smallest aren't as big as a rabbit. Some live on wide plains, some in the mountains and others climb trees and feed on the leaves. Like antelopes, they bound away on the slightest alarm. If overtaken and attacked, they will fight. The giant kangaroo can kill a man or a dog with one slash of the big-toe claw. A horse it will puzzle and frighten by jumping over it and back again. A small dog that annoys it, the animal is said to pick up in its fore-paws, carry to a nearby pond or brook, and hold under the water until it is drowned.

Here is another odd thing. When feeding, two or three little ones follow each mother in the herd, hopping around her. On the slightest alarm the babies vanish! Not one is in sight as the herd goes bounding away. The little ones are not on their mama's backs, and there are no holes in the ground big enough for them to go into.

Watch the kangaroos feeding in the zoo, and maybe you can solve the puzzle of the disappearing babies. There doesn't seem to be a baby in the pen. Suddenly a little head, no bigger than a mouse's head, pops out of the fur on a mother's breast, like a jack-in-the-box, and pops back again. That is surprise number two. The mother kangaroo has a deep, flat, fur-lined pocket on her stomach. You never suspect such a thing because she can shut the top as tight as your mama can snap the clasp of her shopping bag. She can open it, too, for the little ones to jump in and out.

Kangaroo babies need that pouch. When they are born they are only an inch long—about as big as June bugs—and blind, naked and helpless. They cannot even suck their mother's milk, as kittens and puppies can. Their mouths fasten over the nipples inside the bag, and the mother pumps milk into them every so often. They live in the bag for months, scarcely moving. The first time they come out they must climb up and tumble over the edge of the fur pocket, like little birds leaving the nest. For a long time afterwards they sleep and travel in the pouch. It is a sort of dining and sleeping car to them, and a nice place in which to play hide and seek.