266 Voice of Animals [THIRD WEEK 



offspring this action might be partly instinctive, and each 

 generation would perpetuate it. If it had been an inten- 

 tional act, other nearly related species of lizards would 

 imitate it, as soon as they perceived the success which 

 attended it. 



That many animals have a kind of language is nowa- 

 days admitted to be a truism, but this is more evident 

 among mammals and birds, and, reviewing the classes of 

 the former, we find a more or less defined ascending com- 

 plexity and increased number of varying sounds as we 

 pass from the lower forms kangaroos and moles to 

 the higher herb-and-flesh-eaters, and particularly monkeys. 



Squeaks and grunts constitute the vocabulary, if we 

 dignify it by that name, of the mammals. The sloths, 

 those curious animals whose entire life is spent clinging to 

 the underside of branches, on whose leaves they feed, may 

 be said almost to be voiceless, so seldom do they give 

 utterance to the nameless wail which constitutes their 

 only utterance. Even when being torn to pieces by an 

 enemy, they offer no resistance and emit no sound, but 

 fold their claws around their body and submit to the 

 inevitable as silently and as stoically as did ever an 

 ancient Spartan. 



Great fear of death will often cause an animal to utter 

 sounds which are different from those produced under any 

 other conditions. When an elephant is angry or excited, 

 his trumpeting is terribly loud and shrill; but when a 

 mother elephant is "talking" to her child, while the same 

 sonorous, metallic quality is present, yet it is wonderfully 

 softened and modulated. A horse is a good example of 



