THE LIFE OF MAMMALS 
Somaliland and southward to the Mt. Kenia range, — a coun- 
try arid and open or thinly wooded. Two or three allied species 
or varieties are designated in the books. 
The gaudy striping of these animals has caused much specu- 
lation. Professor Osborn is of the opinion that it is a trait 
Colora- acquired comparatively recently, under the brilliant 
som sunshine-and-shadow conditions of Africa, where the 
zebras have taken an opposite course of development in this re- 
spect from the horses and asses. The whole family, he believes, 
has inherited a tendency toward stripings from American Mio- 
cene ancestors for which transversely striped hides were useful, 
by making them less conspicuous in the partly forested kind of 
country which then probably prevailed. Wild ponies and asses 
yet show traces of such markings as occasionally do domestic 
colts; for example, the striped duns of the southwestern United 
States. But while in the plains-dwelling horses and asses the 
stripings have practically disappeared, in the zebras they have 
become intensified, because, as he says, these animals have kept 
themselves mainly in situations where sparse trees cast shadows. 
The hunters do not say much about it, apparently never having 
noticed more difficulty in getting a good sight of a zebra than 
of any other game; but some scientific travelers have asserted 
that the vividly contrasted colorings of the zebras are really pro- 
tective. Schillings’ does so, and Dr. J. W. Gregory, in his 
fine book, ‘The Great Rift Valley,” writes as follows: — 
“The ornamentation of the zebra was also a puzzle to me till I saw them 
at home. The ordinary explanation of striped animals, such as the tiger, 
is that stripes resemble bands of light seen through tall grasses and jungle. 
But this is not applicable to the zebra, which lives in open plains. Watch 
the zebra on these, however, and the value of the coloration is apparent. 
At a distance of from 250 to 300 yards the ‘stripes of the East African 
species (Equus behmi, similar to E. greyvi) cease to be visible and 
the animal appears of a dull gray color. . . In dull, cloudy weather, and 
especially at dawn and sunset, which are the most dangerous times for game, 
the zebra is practically invisible at a distance of over five hundred yards. 
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