ADAPTATIONS 423 



cal contrivances to resist and deaden shock all point exclusively 

 to the correctness of the surmise as to the use of this " ham*- 

 mer ". 



Both Hornbills and Toucans live chiefly on fruit, but the 

 former display a fondness for insect food. The great length 

 of the beak of the Toucan has been explained by Bates in his 

 Travels on the Amazons. " It is," he says, " to enable [it] to 

 reach and devour fruit whilst remaining seated, and thus to 

 counterbalance the disadvantage which the heavy body and 

 gluttonous appetite would otherwise give it in the competition 

 of allied groups of birds. The relation between the extra- 

 ordinarily lengthened bill of the Toucan and its mode ot 

 obtaining food is therefore precisely similar to that between the 

 long neck and lips of the giraffe and the mode of browsing of 

 the animal. The bill of the Toucan can scarcely be considered 

 a very perfectly formed instrument for the end to which it is 

 applied . . . but nature appears not to invent organs at once 

 for the functions to which they are now adapted, but avails 

 herself here of one already existing structure or instinct, there 

 of another, according as they are handy, when need for further 

 modification arises." 



With the Trogons and Barbets we must complete our re- 

 view of fruit-eating birds. Here the beak is extremely short 

 and wide, giving the bird an enormous gape, only exceeded by 

 certain insectivorous birds, such as Swallows and Night-jars, 

 which, it will be remembered, seize their prey upon the wing. 

 Now it is in a precisely similar way that the Trogon plucks its 

 fruit. "Their method of obtaining food," says Bates, "is to 

 station themselves quietly on low branches in the gloomy shade 

 of the forest and eye the fruits on the surrounding trees, darting 

 off as if with an effort every time they wish to seize a mouthful, 

 and returning to the same perch." 



The peculiar habits of feeding displayed by the Toucan and 

 Trogon are the result of adaptation to the peculiar requirements 

 of their environment. Flowers and fruit on the crowns of large 

 trees of South American forests grow chiefly on the small end- 

 twigs which will not bear any considerable weight. All animals 

 therefore which feed on fruit or insects lurking in flowers, must 

 have some means of reaching their food at a distance. Monkeys 

 contrive to do this by their long arms, or must swing by their 



