The three other great desert beasts of Asia or Africa--the ostrich, the giraffe, and the camel--are less protectively coloured, for various reasons. Giraffes and ostriches go in herds; they trust for safety mainly to their swiftness of foot, and, when driven to bay, like most gregarious animals, they make common cause against the ill-advised intruder. In such cases it is often well, for the sake of stragglers, that the herd should be readily distinguished at a distance; and it is to insure this advantage, I believe, that giraffes have acquired their strongly marked spots, as zebras have acquired their distinctive stripes, and hyaenas their similarly banded or dappled coats. One must always remember that disguise may be carried a trifle too far, and that recognisability in the parents often gives the young and giddy a point in their favour. For example, it seems certain that the general grey-brown tint of European rabbits serves to render them indistinguishable in a field of bracken, stubble, or dry grass. How hard it is, either for man or hawk, to pick out rabbits so long as they sit still, in an English meadow! But as soon as they begin to run towards their burrows the white patch by their tails inevitably betrays them; and this betrayal seems at first sight like a failure of adaptation. Certainly many a rabbit must be spotted and shot, or killed by birds of prey, solely on account of that tell-tale white patch as he makes for his shelter. Nevertheless, when we come to look closer, we can see, as Mr. Wallace acutely suggests, that the tell-tale patch has its function also. On the first alarm the parent rabbits take to their heels at once, and run at any untoward sight or sound toward the safety of the burrow. The white patch and the hoisted tail act as a danger-signal to the little bunnies, and direct them which way to escape the threatened misfortune. The young ones take the hint at once and follow their leader. Thus what may be sometimes a disadvantage to the individual animal becomes in the long run of incalculable benefit to the entire community.