346 W. H. PEARSALL 



The wild animals use these waters for only a short period if at all, and do 

 not appear to suffer from them in any way. On the other hand the Masai 

 cattle in this area, though apparently able to survive, often show remarkable 

 signs of fluorosis including softened bones and deformed jaws, which are 

 attributed to the continual use of this quahty of water in wet season and dry. 

 It must be supposed that this is a factor which would prevent the use of more 

 normal breeds of stock as it is known to do further east in the Meru district. 

 The wild game are either immune or their mode of seasonal migration 

 enables them to avoid the effects of the toxic waters. 



ADAPTATIONS TO EXTREME HABITATS 



This example may illustrate a general feature involved in the use of any 

 extreme or 'difficult' habitat. Are not the organisms making up the natural 

 eco-systems likely to be better adapted to existence there than would be 

 any domesticated or imported animal or plant? A biologist might well argue 

 that the natural eco-system has taken ages to evolve and its successful 

 existence shows that the dominant organisms have at least achieved survival 

 value. Imported organisms are likely to lack the essential adaptations unless 

 brought from a closely similar environment. 



One of the striking features of the plains game in my experience has been 

 the magnificent condition in which they appear even under arid conditions 

 which seem to be far from ideal for grazing animals. Physiologists and 

 veterinary officers have discussed the possibihty that some features of the diet 

 might exist on these arid grasslands which particularly improve the protein 

 metabolism or act in the animal body in a protein-sharing role. This would 

 be a favourable factor in addition to the fairly high protein content of some 

 of the grasses eaten. A difficulty is that even the native breeds of cattle do not 

 flourish in the same way, and their condition is generally markedly inferior 

 to that of the wild game — even though they can survive in conditions 

 which would rapidly prove lethal to European cattle. In the case of the 

 African buffalo, it has been found (Harthoom, 1959) that these animals will 

 thrive and gain in weight on natural grasses which will not serve to maintain 

 weight even in the native cattle. The buffalo will give larger gains in weight 

 than either native or European domesticated animals on most forms of 

 native herbage. 



There seems to be Uttle doubt that domestic cattle suffer from various 

 physiological disadvantages in this environment. The improved European 

 breeds, for example, suffer from the fact that the hair length or coat length 

 is controlled by daily light duration. In the relatively short 12-hour day of 

 the tropics, breeds from temperate climates produce their long 'winter 



