"I know!" cried Peter Rabbit. "You mean Jerry Muskrat."

"Go to the head of the class, Peter," said Old Mother Nature, smiling. "Jerry is the very one, the largest member of the Rat family. Sometimes he is spoken of as a little cousin of Paddy the Beaver. Probably this is because he looks something like a small Beaver, builds a house in the water as Paddy does, and lives in very much the same way. The truth is, he is no more closely related to Paddy than he is to the rest of you. He is a true Rat. He is called Muskrat because he carries with him a scent called musk. It is not an unpleasant scent, like that of Jimmy Skunk, and isn't used for the same purpose. Jerry uses his to tell his friends where he has been. He leaves a little of it at the places he visits. Some folks call him Musquash, but Muskrat is better.

"Jerry is seldom found far from the water and then only when he is seeking a new home. He is rather slow and awkward on land; but in the water he is quite at home, as all of you know who have visited the Smiling Pool. He can dive and swim under water a long distance, though not as far as Paddy the Beaver."

"Has he webbed hind feet like Paddy?" piped up Jumper the Hare.

"Yes and no," replied Old Mother Nature. "They are not fully webbed as Paddy's are, but there is a little webbing between some of the toes, enough to be of great help in swimming. His tail is of greater use in swimming than is Paddy's. It is bare and scaly, but instead of being flat top and bottom it is flattened on the sides, and he uses it as a propeller, moving it rapidly from side to side.

"Like Paddy he has a dark brown outer coat, lighter underneath than on his back and sides, and like Paddy he has a very warm soft under coat, through which the water cannot get and which keeps him comfortable, no matter how cold the water is. You have all seen his house in the Smiling Pool. He builds it in much the same way that Paddy builds his, but instead of sticks he cuts and uses rushes. Of course it is not nearly as large as Paddy's house, because Jerry is himself so much smaller. It is arranged much the same, with a comfortable bedroom and one or more passages down to deep water. In winter Jerry spends much of his time in this house, going out only for food. Then he lives chiefly on lily roots and roots of other water plants, digging them up and taking them back to his house to eat. When the ice is clear you can sometimes see him swimming below."

"I know," spoke up Peter Rabbit. "Once I was crossing the Smiling Pool on the ice and saw him right under me."

"Jerry doesn't build dams, but he sometimes digs little canals along the bottom where the water isn't deep enough to suit him," continued Old Mother Nature. "Sometimes in the winter Jerry and Mrs. Jerry share their home with two or three friends. If there is a good bank Jerry usually has another home in that. He makes the entrance under water and then tunnels back and up for some distance, where he builds a snug little bedroom just below the surface of the ground where it is dry. Usually he has more than one tunnel leading to this, and sometimes an opening from above. This is covered with sticks and grass to hide it, and provides an entrance for fresh air.

"Jerry lives mostly on roots and plants, but is fond of mussels or fresh-water clams, fish, some insects and, I am sorry to say, young birds when he can catch them. Jerry could explain where some of the babies of Mr. and Mrs. Quack the Ducks have disappeared to. Paddy the Beaver doesn't eat flesh at all.

"Jerry and Mrs. Jerry have several families in a year, and Jerry is a very good father, doing his share in caring for the babies. He and Mrs. Jerry are rather social and enjoy visiting neighbors of their own kind. Their voices are a sort of squeak, and you can often hear them talking among the rushes in the early evening. That is the hour they like best, though they are abroad during the day when undisturbed. Man is their greatest enemy. He hunts and traps them for their warm coats. But they have to watch out for Hooty the Owl at night and for Reddy Fox and Old Man Coyote whenever they are on land. Billy Mink also is an enemy at times, perhaps the most to be dreaded because he can follow Jerry anywhere.

"Jerry makes little landings of mud and rushes along the edge of the shore. On these he delights to sit to eat his meals. He likes apples and vegetables and sometimes will travel quite a distance to get them. Late in the summer he begins to prepare for winter by starting work on his house, if he is to have a new one. He is a good worker. There isn't a lazy bone in him. All things considered, Jerry is a credit to his family.

"But if Jerry is a credit to his family there is one of its members who is not and that is—who knows?"

"Robber the Brown Rat," replied Happy Jack Squirrel promptly. "I have often seen him around Farmer Brown's barn. Ugh! He is an ugly-looking fellow."

"And he is just as ugly as he looks," replied Old Mother Nature. "There isn't a good thing I can say for him, not one. He doesn't belong in this country at all. He was brought here by man, and now he is found everywhere. He is sometimes called the Norway Rat and sometimes the Wharf Rat and House Rat. He is hated by all animals and by man. He is big, being next in size to Jerry Muskrat, savage in temper, the most destructive of any animal I know, and dirty in his habits. He is an outcast, but he doesn't seem to care.

"He lives chiefly around the homes of men, and all his food is stolen. That is why he is named Robber. He eats anything he can find and isn't the least bit particular what it is or whether it be clean or unclean. He gnaws into grain bins and steals the grain. He gets into hen-houses and sucks the eggs and kills young chickens. He would like nothing better than to find a nest of your babies, Peter Rabbit."

Peter shivered. "I'm glad he sticks to the homes of men," said he.

"But he doesn't," declared Old Mother Nature. "Often in summer he moves out into the fields, digging burrows there and doing great damage to crops and also killing and eating any of the furred and feathered folk he can catch. But he is not fond of the light of day. His deeds are deeds of darkness, and he prefers dark places. He has very large families, sometimes ten or more babies at a time, and several families in a year. That is why his tribe has managed to overrun the Great World and why they cause such great damage. Worse than the harm they do with their teeth is the terrible harm they do to man by carrying dreadful diseases and spreading them—diseases which cause people to die in great numbers."

"Isn't Robber afraid of any one?" asked Peter.

"He certainly is," replied Old Mother Nature. "He is in deadly fear of one whom every one of you fears—Shadow the Weasel. One good thing I can say for Shadow is that he never misses a chance to kill a Rat. Wherever a Rat can go he can go, and once he finds a colony he hunts them until he has killed all or driven them away.

"When food becomes scarce, Robber and his family move on to where it is more plentiful. Often they make long journeys, a great number of them together, and do not hesitate to swim a stream that may be in their path."

"I've never seen Robber," said Peter. "What kind of a tail does he have?"

"I might have known you would ask that," laughed Old Mother Nature. "It is long and slim and has no hair on it. His fur is very coarse and harsh and is brown and gray. He has a close relative called the Black Rat. But the latter is smaller and has been largely driven out of the country by his bigger cousin. Now I guess this is enough about Robber. He is bad, all bad, and hasn't a single friend in all the Great World."

"What a dreadful thing—not to have a single friend," said Happy Jack.

"It is dreadful, very dreadful," replied Old Mother Nature. "But it is wholly his own fault. It shows what happens when one becomes dishonest and bad at heart. The worst of it is Robber doesn't care. To-morrow I'll tell you about some of his cousins who are not bad."