USE OF NATURAL INSTRUMENTS. 427 



oyster-shells (Dampier). In the commoner case of birds, 

 shell-fish are either dropped from a height on stones or rocks 

 or, held in their beaks or bills, they are dashed violently 

 against stones. 



Various thrushes, especially, are in the habit of smashing 

 snail-shells on or against stones. In our own country it is 

 a habit of the common thrush to do so by grasping the 

 snail-shell in its bill and bringing it down with force on a 

 stone usually some particular or favourite stone, round 

 which may be found a whole heap of shell debris a minia- 

 ture 'kitchen midden' ('Animal World'). The mavis breaks 

 the shell of Helix nemoralis 'by reiterated strokes against some 

 stone. ... It is not uncommon to find a great quantity of 

 fragments of shells together, as if brought to one particular 

 stone for that purpose ' (Montagu). There are, in fact, some- 

 times small ' shell-mounds ' about these favourite ' anvils,' 

 as Atkinson calls them. The sacred kingfisher of Australia 

 kills small snakes by * beating their heads against a stone or 

 other hard substance' (Jesse). The caama (asse or swift fox) 

 of Southern Africa is said to break the eggs of the ostrich 

 by rolling them with its paws ' forcibly against a stone or 

 other hard substance.' Boddam Whetham mentions a large 

 land-crab of Samoa that, after having removed the husk of 

 the cocoa-nut, carries the nut to the top of a tree, and lets it 

 fall upon a rock or stone, so as to break it. 



Stones are also used as wedges by apes (Watson). Thus 

 they * push stones between the open valves of the mussel- 

 shell to prevent their closing' (Biichner). Certain birds em- 

 ploy stones for their weight as keep-fasts for instance, in 

 the bowers of bower birds (Nichols). And certain spiders 

 use fragments of gravel to steady their webs. 



The elephant breaks off leafy branches for the purpose 

 of using them variously as (1) fans or punkahs ; (2) whisks, 

 to brush or ward off flies or other insect plagues ; (3) sun- 

 shades (Watson). 



Certain of the anthropoid apes make a kind of tente 

 d'abri, a rude sort of hut, of the branches and leaves of 

 trees a dwelling quite c'omparable with the shelters con- 

 structed for themselves by the various primitive people who 



