190 
EASTERN ETHIOPIA 
XV 
Zebras are, in a sense, a pest; wandering over tlie 
plain, they break down fences and trample over culti¬ 
vated areas. They are good friends with ostriches, 
hartebeests, and Thomson’s gazelles. The hartebeests 
are the friends and guides of zebras, and the latter 
never neglect the sentinel’s signal of alarm. 
Zebras will disappear before the march of civilisation ; 
the lion takes a heavy toll of them, l)ut the settler is 
the bigger foe. In the grass land around Nakuru we 
saw their skeletons in abundance picked clean by 
vultures and bleached by sun and weather. 
The presence of so many zebra skeletons in the grass- 
covered crater-like depressions around Nakuru recalled 
to my mind a fact often referred to by geologists, 
namely, the great accumulation of mammalian bones in 
a limited area. Sometimes the bones are those of the 
same species of vertebrate animal, or they may be a 
mixture of incongruous species. Several explanations 
have ])een advanced to account for such local collections 
of skeletons. 
Darwin, in his delightful account of the voyage of the 
Beagle refers to this in regard to the Guanaco, for he 
writes that they have particular spots for lying down 
to die, and that in certain circumscribed spots on the 
banks of the St. Cruz river the ground was actually 
white with bones. He particularly examined the bones 
and points out that they were not gnawed or broken. 
He came to the conclusion that “ the animals in most 
cases must have crawled, before dying, beneath and 
amongst the bushes.” Darwin also mentions that at St. 
Jago in the Cape de Verd Islands he found, in a ravine, 
a retired corner covered with bones of the goat, and 
exclaimed that it was the burial ground of all goats 
in the island. 
It appears that the Swahili traders believe in 
natural “ animal cemeteries ” ; Major Powell-Cotton 
describes one which he visited near Mount Zunut in the 
Toposa Country. He was surprised to find the whole 
