When we watch a collie at a sheep-driving competition, or an elephant
helping the forester, or a horse shunting waggons at a railway siding,
we are apt to be too generous to the mammal mind. For in the cases we
have just mentioned, part of man's mind has, so to speak, got into the
animal's. On the other hand, when we study rabbits and guinea-pigs, we
are apt to be too stingy, for these rodents are under the average of
mammals, and those that live in domestication illustrate the stupefying
effect of a too sheltered life. The same applies to domesticated sheep
contrasted with wild sheep, or even with their own lambs. If we are to
form a sound judgment on the intelligence of mammals we must not attend
too much to those that have profited by man's training, nor to those
whose mental life has been dulled by domestication.