COLOURS AND PATTERNS OF MAMMALS 95 



infrequently traces of them occur in foals and fade out when the 

 colouring of the adult has been reached. It is difficult to resist 

 the conclusion that a striped pattern is primitive in the group and 

 represents a natural growth pattern which is in course of oblitera- 

 tion. Grevy's zebra is the most completely striped of all the 

 animals in the group, and the other zebras show a gradual transition 

 to the unstriped donkeys, some of the stripes fading out and ap- 

 pearing only as shadow stripes, the stripes on the legs and under side of 

 the body disappearing next, until the quagga pattern is reached, an 

 animal which was not much more marked than many donkeys. When 

 zebras are crossed with horses, the stripes are more niunerous even 

 than in the Grevy zebra, but are extremely faint. When they 

 are crossed with donkeys, the stripes are more numerous than in 

 donkeys and very brilliant, but less numerous than in zebras. 



The conies or hyraxes resemble their parents in coloration very 

 closely, but are generally rather darker, and the young of different 

 species are more alike than the adults. 



Young elephants are lighter in colour and much more hairy 

 than the adults. 



Nearly all the Rodents are quietly coloured creatures with little 

 or no difference in pattern between the males and females. They 

 are the prey of many enemies and have little powers of defence. 

 They are disposed to avoid daylight, coming out just before dusk 

 and again in the very early morning about dawn. Their subdued 

 hues suit their habits. They are usually self-coloured with more 

 or less of counter-shading. A few are striped or spotted, the stripes 

 or rows of spots always being arranged along the length of the animal. 

 Some of them, however, and particularly the squirrels, are vividly 

 coloured, the colours being in great masses or patches. There are 

 usually two moults in the year, the winter pelage being duller and 

 less brightly patterned, whilst the vivid colours are assumed for the 

 breeding season. The young are often bom in underground nests, 

 in hollow trees, or in other dark and well-concealed places, and 

 those that are produced in such nurseries are very immature, naked 

 and blind. On the other hand, if, as in the hare, the young are 

 born in the open fields, and have to run the danger of being dis- 

 covered by enemies, they come into the world in a more mature con- 

 dition, able to see, and clad with fur. When the first coat of fur 

 has been gained, it is striped like that of the adult, in the striped 

 forms ; in others it is a paler imitation of the adult pattern. 



The Marsupials are still more quietly coloured than rodents, a 



