The claws of every feline are _retractile_. That is, the claws can be _drawn in_, or sheathed, whenever the animal desires; also, the claws can be thrust out, whenever the animal desires to do that. Why is it necessary for a feline to be able to do both--to draw in its claws, and to thrust them out? Because when the animal needs food, it must thrust out the claws to seize it. But in just running about in the jungle, it does not need to use its claws; so it draws them in. In fact, if it did not draw in its claws then, the claws would soon be worn out by rubbing against the ground. And even if the claws were growing all the time, they would be also wearing off all the time. So to keep the claws sharp for use only when the animal wants to seize something, it keeps the claws drawn in at other times. Here I ought to tell you that a dog's claws are quite different from the claws of a feline, even from those of an ordinary cat. The cat's claws are of course retractile, as I have just described to you. But a dog's claws are _rigid_; that is, they are stiff and thrust out all the time. Why? Because the dog does not use its claws. It seizes its food with its mouth, not with its claws. It even defends itself with its mouth, that is, with its teeth. But a feline uses its claws to seize its food, and even to defend itself. You may have noticed that even an ordinary cat defends itself with its claws. When a dog chases a cat and corners it, the cat turns and defends itself with its claws. Once upon a time, many, many hundred years ago, the dog did use its claws; they were then retractile. But the dog stopped using its claws; then they became rigid. The dog lost the power of drawing in its claws. In our own bodies, if we do not use a particular gift for a long time, we lose the power of using that gift. When we are born, our left hand is just as good as our right hand. But because we do not use the left hand much in doing things, we lose the power of using it quite as well as we use the right hand. Little boys and girls should practice using the left hand. Then if by some accident the right hand is lost, they would not be quite helpless. As for the felines, they retain the full power of their claws by constant use. So, because the claws are very useful, every feline takes care of its claws,--especially the tiger. Why, _the tiger cleans his claws every day_! In the jungle there are many trees that have a soft bark. So the tiger goes to one of these trees every day, and digs his claws into the bark. Then he draws his claws sideways along the bark, and that cleans out the claws. The tigress also cleans her claws every day in the same manner.