The bifid extremity of their tongues, soft and always moist, is most probably an organ delicate to touch and probably to taste. They never cease to project it forward on to all the things within their reach, and although accustomed to meal worms, they begin generally by feeling them—at least the first one—in this way before taking them. The whip-tails (Uromastix) do the same, and when set down in the grass test all the flowers with their tongue. I should observe further that these animals did not hibernate with me, and that they were as lively and active in winter as in summer. The same may be said of two jerboas which I kept in captivity for three years and a half. Hibernation, therefore, does not seem to be a physiological necessity, but to be rather a natural effect of the cold, like the depression of the thermometer. The lizards were very fond of keeping themselves in front of the registers.
I now come to a trait which on reflection appears to me to be characteristic in the highest degree. Jealousy is a feeling not less natural to animals than to us. The males compete in strength, beauty, or talent to conquer the females. Beasts of prey, from spiders to lions and eagles, enforce respect of their hunting grounds. All defend their bed, their burrow, or their nest; and probably, too, herbivorous animals living in herds do not permit other herds to trespass upon their pastures. The jealousy of the dog is well known; if he is left alone, he will eat the part of the cat, and even rob the pigs of their messes. I have kept two jerboas for three years, all very familiar. Every evening we give each of them an almond, which they come and take out of the hand, and even ask for. But hardly has one received hers than, without paying any more attention to us, the other pursues her, takes it away from her, and a struggle ensues—a struggle which is otherwise courteous. The same play is acted when dandelions are given to them; hardly has one detached a leaf when the other tries to snatch it from her.
My lizards did not vary from the general rule. The best worm was always the one that a comrade had. If it was long, we might witness such a steeplechase as is seen sometimes in poultry yards.
Pedro was jealous of my preference and caresses. When he was on my sleeve, I could keep him for hours motionless by passing my hand lightly along his body; but if I took Pierre or another lizard up, his rage broke out at once, and he would jump upon him with his mouth menacingly wide open. If, however, I chose the large lizard, he gradually drew back, as if regretfully, without leaving me. Now, what good do caresses do to a lizard? Dogs and cats, they tell us, are delighted with them. But these animals, when they were young, were caressed by their mothers, who licked, bit, and amused them, and it is not strange
