Though he didn’t realize it then, this last was the most important lesson of all. It was the great lesson that human beings have been so long learning, and which many have not learned yet, that, just in proportion as each one looks out for the welfare of his neighbors, he is himself better off. Instead of having just one pair of little eyes and one pair of keen little ears to guard him against danger Tommy had many pairs of little eyes and little ears keeping guard all the time, some of them better than his own.
Eating, sleeping, and playing, and of course watching out for danger, were all that Tommy had to think about through the long lazy summer, and he grew and grew and grew until he was as big as the biggest muskrats in the Smiling Pool, and could come and go as he pleased.
There was less to fear now from Hooty the Owl, for Hooty prefers tender young muskrats. He had learned all about the ways of Reddy Fox, and feared him not at all. He had learned where the best lily-roots grow, and how to find and open mussels, those clams which live in fresh water. He had a favorite old log, half in the water, to which he brought these to open them and eat them, and more than one fight did he have before his neighbors learned to respect this as his. He had explored all the shore of the Smiling Pool and knew every hole in the banks. He had even been some distance up the Laughing Brook. Life was very joyous.
But, as summer began to wane, the days to grow shorter and the nights longer, he discovered that playtime was over. At least, all his friends and neighbors seemed to think so, for they were very, very busy. Something inside told him that it was time, high time, that he also went to work. Cold weather was coming and he must be prepared. For one thing he must have a comfortable home, and the only way to get one was to make one for himself.
Of course this meant work, but somehow Tommy felt that he would feel happier if he did work. He was tired of doing nothing in particular. In his roamings about, he had seen many muskrat homes, some of them old and deserted, and some of them visited while the owners were away. He knew just what a first-class house should be like. It should be high enough in the bank to be above water at all times, even during the spring floods, and it should be reached by a passage the entrance to which should at all times be under water, even in the driest season.
On the bank of the Smiling Pool grew a tree, and the spreading roots came down so that some of them were in the Smiling Pool itself. Under them, Tommy made the entrance to his burrow. The roots hid it. At first the digging was easy, for the earth was little more than mud; but, as the passage slanted up, the digging became harder. Still he kept at it. Two or three times he stopped and decided that he had gone far enough, then changed his mind and kept on. At last he found a place to suit him, and there he made a snug chamber not very far under the grass-roots.
When he had finished it, he was very proud of it. He told Jerry Muskrat about it. “Have you more than one entrance to it?” asked Jerry.
“No,” replied Tommy, “it was hard enough work to make that one.”
Jerry turned up his nose. “That wouldn’t do for me,” he declared. “A house with only one entrance is nothing but a trap. Supposing a fierce old mink should find that doorway while you were inside; what would you do then?”
Tommy hadn’t thought of that. Once more he went to work, and made another long tunnel leading up to that snug chamber; and then, perhaps because he had got the habit, he made a third. From one of these tunnels he even made a short branch with a carefully hidden opening right out on the meadow, for Tommy liked to prowl around on land once in a while. The chamber he lined with grass and old rushes until he had a very comfortable bed.