[9]. Animal Coloration, by F. E. Beddard, M.A., Prosector to the Zoological Society of London. Swan, Sonnenschein, and Co., London. Macmillan and Co., New York.
The mode by which, in the simple organisms which he observed, the colour was transferred from the food to the feeder, also suggests the existence of some simple and natural relation between the tints in the skin, or hair, and external conditions of food and temperature, to account for the strange changes of colour to suit outside conditions in animals exposed to the rigours of a northern winter. The mountain hare of Ireland does not always change its colour to white in winter, though in the colder climate of Scotland and Norway the change is the rule. So the Arctic fox seems always to be “bleached” in the extreme north, though often retaining its darker dress throughout the year when further south. Yet exactly the same effects are found in connection with want of food as with want of warmth. The rats in a large iron ship which was recently wrecked off the coast of Northumberland,[[10]] and remained stranded for many weeks without connection with the shore, turned quite white—a change due apparently to starvation.
[10]. Near Blyth. When some shipwrights visited the vessel to remove rigging and fittings, the starving rats swarmed round them, and ate the food which they had brought for their dinners.
In strong contrast with the modifications of the part played by evolution in animal colouring, suggested by Dr. Eisig, is the alternative which Mr. Stoltzmann proposes to the theory of sexual selection. It is not a change which will flatter the masculine imagination. Contrasted with the view which accounted for the predominance of male strength, and in some cases of masculine beauty, over the weaker sex by a long course of discerning feminine selection, it has an unconscious irony. Going quite outside the merits of the male sex per se, Mr. Stoltzmann weighs its worth in view of the survival of a species. So considered, an excess of males is an evil, which the law of natural selection is under obligations to remedy.[[11]] The tendency of Nature is to produce a superabundance of males, observations on the origin of sex having shown that the percentage of male birds among birds is greater than that of females. Further inquiries into the influence of nutrition on sex go to show that badly-nourished eggs produce males, while well-nourished eggs produce females; and scarcity of food is a more common condition than its abundance. The fine feathers which “make fine birds” have therefore been given to the males with a view to exposing them to the attacks of their enemies, and so reducing their numbers, always—be it observed—in accordance with the law of the survival of the fittest, but by a curiously different line of argument from that which lent its weight to the theory of sexual selection. Probably neither the one nor the other should stand alone; nor is this result to be feared. Bigotry seems almost unknown to the spirit of the natural history research of to-day; the only danger of the open mind of its followers is in the constructive ingenuity of theory which it seems to foster.
[11]. The bad result of an excess of males is perhaps best ascertained in the case of grouse moors. See Mr. A. Stuart Wortley’s remarks upon this in The Grouse (Fur and Feathers Series, Longmans, Green & Co.).
WILD-CATS AT THE ZOO.
The reservation of one-tenth of the area of Scotland for deer-forests has probably arrested the extermination of three, if not of four, of the largest and rarest of our birds and beasts of prey for at least a century. The great increase in the numbers of the golden eagle, and the migration of the ospreys from the lakes to the forests, are among the results of the protection so afforded. It was reasonable to expect that the wild-cat would also benefit by the policy, now generally in favour with owners of forests, of encouraging animals of prey to keep down the grouse and hares. The arrival at the Zoological Gardens of two genuine Scotch wild-cats, trapped during last year on the same estate in Inverness-shire, is evidence that even there the rarest and wildest of all British quadrupeds are recovering from the persecution of half a century of grouse and black-cock preserving. Both were caught in steel traps, and each had lost part of a fore-foot; but with the wonderful vitality of all cats, they so far recovered from their injuries that, on being confronted with each other, they at once joined battle, like the Border rider at Chevy Chase, who—
“When his legs were smitten off,
Did fight upon his stumps.”