ZEBRA'S STRIPES

Evening Post, Volume CXVI, Issue 142, 13 December 1933, Page 7

ZEBRA'S STRIPES

DO JHEY, S CONCEAL ?

IS THEORY OVERDONE?

At last a long-expected challenge/to theories of protective coloration (or at least to some applications of s^ch theory) has arrived. Mr, Eric Pockley writes to :a Sydney paper complaining that protective colouration has ■ been exaggerated, and 'denying that ' the zebra enjoys it except on • occasions. He quotes a recent statement made in Sydney to the effect that some of the most striking colour patterns are the most concealing, and, as an example of this, that a man walked right into a herd of about 40 zebra before he was aware of their presence. Mr. Pockley comments:— "Of course, there-is no doubt about the fact of protective coloration, and I think most of the examples he gives are true enough, but like the fact.of mimicry in the songs of birds, I think it is worked to death, and that often it is claimed when it does not exist. Surely many animals survive in spite of, rather than on account of, their colouration, by the possession of other assets, such as speed of foot, acuteness of sight and hearing, etc.. For example, the little Thompson's gazelle, which has a white rump, and the more nervous it is about something strange the "more it absolutely heliographs its presence by rapidly swishing its dark tail from side' to side, causing a flicker which immediately catches your vision at long distances. • .. "During four,months' expedition by foot in Kenya, zebra were in sight practically every day, sometimes in thousands. They are about the most startlingly coloured and easily seen of all the animals on the African plains, and will arrest your attention, at tremendous distances. I think there must be very fow animals that are less protected by their colour. There is certainly ono peculiarity of their coloration, and that is, that with the sun at one particular angle, they occasionally look entirely black, and at . another angle entirely white, and on one occasion with the naked eye I saw what looked like a row of glistening white tents at least five miles away, and on focusing my glasses on them, was amazed to sco that they were zebra. The .only occasions on which I found them hard to see were when they were in small timber with white stems and branches and a bright. sun overhead, when the bars of light and shade made their detection difficult. "I am 'inclined to think that the man who "walked into a herd of them must have' met them in some such locality; but this is a comparatively rare place to find them, as they spend the greater part of their time on the open plains. It is not our individual opinions that matter much, but as most of these facts of natural history are sooner or later used to substantiate or confound some theory on the riddle of life, or other problems, it is- as well to have the facts as right as possible, and for my part I am doubtful about survival in the case of the zebra, and in the case of many other animals and birds which are often claimed as being associated with protective coloration."