Ii6 CHILDHOOD OF ANIMALS 



It follows of course that the natural rate of mortality must be 

 very high. If each pair of sparrows tend to be turned into about 

 twenty sparrows by the end of the year, and yet the total sparrow 

 population does not increase, eighteen out of twenty must die 

 every year — ^that is to say, the sparrow death-rate must be about 

 ninety per cent., the normal human death-rate in London being 

 only about one and a half per cent, per annum. The death-rate 

 amongst elephants must be smaller ; that amorgst turbot higher. 

 Anyhow, it is plain that death takes a heavy toll of all living things. 



Death falls most heavily on young animals. Physically they are 

 more feeble and more readily succumb to extremes of heat or 

 cold, to starvation or over-eating, to drought or rain, and to disease 

 of all kinds. But their plain destiny is to be eaten. Young animals 

 are more tender and succulent than old ones. Their fur, feathers, 

 scales, bones and other hard parts offer less resistance to the teeth 

 or claws and other biting and grasping organs, and offend the 

 stomachs of their captors less than those of full-grown animals. 

 They are not only a more attractive but an easier prey. They 

 cannot fight or struggle much, they have feebler powers of escape, 

 and less cunning and resource in avoiding their enemies. They 

 form a great part of the food-supply of the world. 



The ultimate source of the food of all animals is green vegetation. 

 A vast expanse of verdure, trees, shrubs, grasses, ferns and moss 

 covers almost the entire surface of the land from the tops of the 

 mountains down to the edges of the sea. All this green vegetation 

 is actively building organic food-material from the inorganic 

 elements of the air and the soil. And so on the land vegetarian 

 animals are more prolific and abundant than carnivorous creatures. 

 Plant-eaters like sheep and cattle, deer and antelopes, rabbits and 

 kangaroos are found in huge numbers and multiply at incredible 

 rates. So also seed- and fruit-eating birds are more numerous 

 than carnivorous birds ; grasshoppers, locusts and vegetarian 

 beetles than their carnivorous allies. But all these are preyed upon 

 by carnivorous mammals, birds, reptiles and insects. In the sea, 

 on the other hand, most of the animals are carnivorous. The 

 birds that live on the ocean, terns, gulls, petrels, cormorants, 

 are very numerous indeed, and the clouds of sea-birds in their 

 breeding-places recall the dense vegetarian population of the land. 

 These sea-birds are all carnivorous ; most of them are fishers, and 

 others, like the petrels, scoop up the small Crustacea from the 

 surface of the waves. Seals pursue fishes ; polar bears live on 



