EXTERNAL ANATOMY. THE NECK. 27 
goatsuckers, &c., is in some measure attributable to the 
same cause, although in a far less degree. 
(36.) The NECK attaches the head to the body : some- 
times this part is very long, not only in birds, but in 
certain quadrupeds. The use, however, of this unusual 
prolongation is various. \n\Aie Camelopardalis it enables 
the animal to reach the branches of the taU mimosas, 
whose leaves constitute its chief nourishment. In the 
perching order of birds, Tnsessores, the only examples of 
this sort are found among the woodpeckers*, whose pe- 
culiar method of picking holes in trees, by the force of 
repeated strokes of the bill, obhges them to throw the 
head very backward without elevating the body : this 
they are enabled to do by their long neck ; an additional 
force, or impetus, is thus given to every blow, just as a 
person who wishes to strike hard with a hammer, ele- 
vates his hand in proportion to the blow he wishes to 
produce. Nearly all other insessorial birds have short 
necks, for no such exertion as we have just described is 
requisite to procure their food; and their constant habit 
of perching on the branches of trees, renders it unneces- 
sary that they should be more elevated for the purpose of 
discerning the approach of danger. Among birds, how- 
ever, which have feeble wings anri live habitually upon 
the ground, like the rasorial order, the neck is much 
more developed. This may be intended to effect two 
purposes ; first, to give a greater scope of vision, as a 
security against danger ; and, secondly, to facilitate the 
act of feeding. It is evident that birds attach the feel- 
ing of security to elevation ; for nearly all those which 
habitually live only upon the ground, roost in branches, 
W’here they can see much farther, and discern the ap- 
proach of an enemy. On the other hand, as the 
gallinaceous order, like the turkey and the peacock, 
have generally high legs, a long neck is essential to 
avoid any difficulty in feeding and picking their food 
from the ground, close to which the head must reach 
• This is doubtless one of the analogies between the herons and the 
■PfctdlB. 
