Page:Popular Science Monthly Volume 62.djvu/351
TEE BEHAVIOUR OF BLIND ANIMALS. 345
at the mercy of his enemies, and yet not to the degree one might have supposed on account of his greater caution as well as the fact that his senses of touch and smell make up so fully for the lack of sight. It must be borne in mind that the olfactory tracts of the central nervous system in the rat are highly developed and their association-paths numerous, so that in an eminent degree the rodent, and especially the rat, is worked, so to speak, as an entire mechanism largely through the reflex paths of smell.
One of the unexpected results of sudden blindness in the case of white rats, whether affecting one or both eyes, was a most marked alteration in disposition. Eats that were perfectly tame became at once ferocious ; it was unsafe any longer to attempt to handle them as f or- merfy, or to remove anything from their cage, for in an instant they seemed aware of the approach of one's hand and were not only ready but able to pounce upon it at once; even metal forceps were seized by the teeth. After a considerable period in a rat blind in both eyes this ferocity disappeared, but not so, or to but a slight extent, in those lacking the power of vision on only one side.
In our experience in the breeding of white rats, it is rare for the female to devour her young, but invariably have those blind white rats killed and eaten to a greater or less extent every litter they have had, though placed under circumstances exactly similar to those of the intact rats.
Babbits. My opportunities to observe this species of rodent when blindness was found on one or both sides, has been almost as good as in the case of the rat. The differences noted in the animals is considerable. A rabbit totally blind behaves in general much like a rat similarly defective, but he shows less tendency on occasion to retreat towards his place of safety, is less alert and apparently less prepared to meet emer- gencies. But the readiness with which he manages to avoid obstacles in his path is striking. He also, like the rat, stretches out his neck, rises sometimes on his hind legs, but more frequently raises the fore parts of his body into the air, all with the obvious purpose of exploring the nature of his environment to a degree and with a frequency not witnessed in the normal rabbit. Such an animal is, however, more likely to fall under the power of his enemies than is the rat, though so long as food is plenty near his burrow the wild animal would no doubt develop that caution and use his other senses to such an extent that he would generally escape ; but that he would in the long run fall a prey to some wily fox seems more than probable.
I have noticed no change in disposition in the case of the rabbit akin to that in the rat and none of the blind specimens has had young.
Neither the rabbits nor the rats ever make the mistake of walking off a place elevated above terra firma. As I have elsewhere pointed out,