“That is just what the cat can do at will. Let us examine this curious mechanism more closely. The little terminal bone of the toes, the one that bears the claw, is fastened to the preceding little bone by an elastic ligament, the effect of which, in a state of repose, is to raise the first bone and rest it on top of the second. Suppose that the tips of your fingers had play enough to fold back: there you have an exact representation of the process. In this position of the terminal bone the claw is held upright, half sunk in a fold of the skin and hidden under the thick fur of the paw.”
“I understand,” said Jules; “then it is a velvet paw; the claws are in their sheaths.”
Cat’s Claws and Tendons
“Promptly, at the call to arms, the cat has but to will it, and its claws spring out. Look at this picture of a cat’s paw and notice what appears to be a network of cords. Those are the tendons which, whenever the animal so desires, are [[257]]pulled by the muscles situated higher up. They are fastened each to the lower side of one of the terminal bones of the toes. Pulled by its tendon, this terminal bone pivots, as if on a hinge, on the extremity of the preceding bone, and gets in a straight line with it. At the same time the pointed end of the claw comes out of the paw.”
“Then the cat’s claws are worked by cords and pulleys!” exclaimed Emile. “It is enough to bewilder one, it is so complicated. But I understand it in the main. To make velvet paws the cat doesn’t have to do anything at all; the claws go in of their own accord and stay in their sheaths; and if they have to be drawn out, the cords or tendons give a pull, and the thing is done.”
“To be shod with soft slippers which both admit of a noiseless approach to the hunted prey and can, on the instant, change into terrible weapons of attack, is not alone sufficient for the hunter’s success; he must also have eyes to guide him in the darkness of midnight, the hour most favorable for an ambuscade. In this respect the cat is admirably equipped. Its eyes are formed for receiving more or less light as may be necessary for seeing.
“Notice a cat in the sun. You will see the pupil of the eyes reduced to a narrow slit resembling a black line. Not to be dazzled by too great light, the animal has closed the passage to the rays of light; it has closed the pupil while leaving the eyes wide open. Take the cat into the shade: the slit of the eyes will enlarge and become an oval. Put it in a [[258]]semi-dark place: the oval opening will dilate to a circle and this circle will grow larger as the light diminishes.
“Thanks to these pupils, which open very wide and can thus still manage to receive a little light where for others it would be pitch-dark, the cat guides itself in the dark and hunts at night even better than in broad daylight, since it remains invisible to the mice while it can see them well enough. Nevertheless, if there were no light, if the darkness were absolute, the cat could not see anything. In this connection, recall what we were saying a while ago about nocturnal birds of prey. Some maintain that a cat sees distinctly in complete darkness; I have shown you, on the contrary, that for every animal without exception sight becomes impossible as soon as there ceases to be even the faintest ray of light.”
“The cat cannot see without some light, I haven’t the slightest doubt,” assented Jules. “But all the same I have known it to hunt in places where not a glimmer of light could get in.”