OF WILD ANIMALS 29 



but he is far from being mute. He appears to be devoid of 

 all risibility, but he is often very noisy. Although diurnal in 

 habit, he talks less frequently during the day than at night, 

 but his silence is a natural consequence of his stealth and 

 cunning. There are times, however, when he ignores all 

 danger of betraying his whereabouts or his movements, and 

 gives vent to a deluge of speech. At night his screams and 

 shouts are terrific." 



The gibbons (including the siamang) have tremendous 

 voices, with numerous variations, and they love to use them. 

 My acquaintance with them began in Borneo, in the dense 

 and dark coastal forest that there forms their home. I re- 

 member their cries as vividly as if I had heard them again 

 this morning. While feeding, or quietly enjoying the 

 morning sun, the gray gibbon (Hylobates concolor) emits in 

 leisurely succession a low staccato, whistle-like cry, like "Hoot! 

 Hoot! Hoot!" which one can easily counterfeit by whistling. 

 This is varied by another whistle cry of three notes, thus: 

 "Who-ee-hoo! Who-ee-hoo!" also to be duplicated by whistling. 

 In hunting for specimens of that gibbon, for American museums, 

 I could rarely locate a troop save by the tree-top talk of its 

 members. 



But all this was only childish prattle in comparison with 

 the daily performances of the big white-handed, and the black 

 hoolock gibbons, now and for several years past residing in 

 our Primate House. Every morning, and perhaps a dozen 

 times during the day, those three gibbons go on a vocal ram- 

 page and utter prolonged and ear-splitting cries and shrieks 

 that make the welkin ring. The shrieking chorus is usually 

 prolonged until it becomes tiresome to the monkeys. In all 

 our ape and monkey experience we never have known its equal 

 save in the vocal performances of Boma, our big adult male 

 chimpanzee, the husband of Suzette. 



A baboon emits occasionally, and without any warning, 

 a fearful explosive bark, or roar, that to visitors is as startling 



