SPECIES OF GIBBONS 



The tail is wanting, as in the highest apes and in man ; 

 and the vermiform appendix is present as in the same. 

 The lower monkeys generally (but not always) possess 

 a tail. So much then for the chief points in the inward 

 and outward structure of the Hoolock and its congeners 

 which help to fix its place in the Simian system. The 

 hoolock, or at least some form of gibbon, is almost sure 

 to be on view in the New Ape House at any given time. 

 It will probably also appeal to another sense, that of 

 hearing ; for this gibbon, like others, has a piercing 

 though not unpleasant voice by means of which it utters 

 a series of cries which have been variously rendered 

 " Hooloo " and " Whoko." It prefers climbing to 

 walking ; and when it does walk, which in nature 

 appears to be practically never, it walks on two legs 

 as a rule, and divaricates its big toe like unbooted 

 man. Its extraordinarily long arms are used in this 

 method of progression as balancing poles to aid in 

 its waddling run. Placed on a tree the gibbon has no 

 equal among the monkey tribe. It swings from 

 bough to bough " with the unerring accuracy of a 

 finished trapeze performer." It is an odd thing that 

 this gibbon at any rate cannot swim, and naturally, 

 therefore, never takes to the water on its own account. 

 Monkeys, as a rule, can, and do voluntarily, set out to 

 swim, crossing rivers in their marches, but the gibbon 

 never ; and thus its range is often limited by great 

 rivers such as the Irrawaddy. In this dislike of water 

 it plainly resembles man, who is almost the only other 

 creature that cannot swim by the light of nature, but 

 requires teaching. The specimens of gibbon that 

 have been on view at the Zoo are numerous, and are 

 of many species. Quite recently there was on view 

 an example of the very rare Hainan gibbon, an ape 

 which frequents the island of Hainan, its easterly limit 

 as a genus. Another rarity is the Siamang, a* gibbon 



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