3 66 ANIMAL DEFENCES 



earned for them their Boer name. They also run in a remarkable 

 zigzagging manner. The Common Koodoo (Strepsiceros kudu\ 

 a large and handsome antelope, is described as rushing in retreat 

 through thickets of " wait-a-bit ", and other thorny plants, in a 

 way that must prove effective in baffling most pursuers, besides 

 which old bulls of this species are credited with rendering them- 

 selves inconspicuous by lying down against a suitable bush and 

 raising their heads so that the large twisted horns rest on the 

 back, a position in which they are not likely to attract attention. 



Perhaps the most interesting device which helps to save many 

 of the weaker Ungulates from their inveterate enemies, the larger 

 Carnivora, is the habit of " ruminating " or " chewing the cud ", 

 which is characteristic of one large group, the Ruminantia. The 

 structural arrangements related to this have been described 

 elsewhere (p. 168), and its protective nature is obvious. A 

 ruminant animal can crop a large quantity of food very rapidly, 

 swallowing it without proper mastication, and then retreating to 

 some comparatively safe place, where the " cud " can be chewed at 

 leisure. In this process the food again returns to the mouth in 

 successive boluses, and is swallowed for a second time after being 

 properly divided and saturated with saliva. 



Many of the Mammalia possess Dwellings, to which they 

 retreat when attacked. Rabbits furnish a particularly good ex- 

 ample, and everyone who has attempted to shoot these animals 

 is familiar with their habit of popping into their burrows with 

 lightning-like rapidity on the least alarm. A favourite time for 

 feeding is just when it begins to get dark, and it is then that the 

 neutral colour of the fur harmonizes best with the general sur- 

 roundings so as to render detection a matter of difficulty. Like 

 so many other social forms rabbits appear to make arrangements 

 for the safety of the community by the more experienced members 

 giving warning of approaching danger. This purpose appears 

 to be served, for example, by the curious and emphatic way in 

 which the old bucks stamp on the ground when alarmed. It is 

 somewhat remarkable that an animal like the rabbit, which is 

 protectively coloured, should have a white under-surface to the 

 tail, being thereby made particularly conspicuous when in motion. 

 This has been interpreted with some probability as a case of 

 ''signalling coloration", enabling the rapid retreat from danger 

 of an individual to be quickly seen by other rabbits in the neigh- 



