144 HABITS AND INSTINCTS OP ANIMALS. CHAP. V. 



hornbills (Buceridai), are used in any manner for self- 

 defence ; but this is not unlikely, since it is asserted 

 that the cassowary which is furnished with a pro- 

 tuberance in every way analogous in external form 

 is capable, in this manner, of inflicting severe bruises. 

 Some few aquatic groups, but more especially the 

 petrels, secrete an oily fluid, which they squirt out upon 

 those who annoy them ; while such as are of a large 

 size, and powerful flight, strike very severely with their 

 wings. 



(163.) Among reptiles, the active powers of defence 

 are almost entirely confined to the teeth, the passive to 

 their covering and their swiftness of motion. On the 

 voracity of the crocodiles we have elsewhere expatiated. 

 They are nearly the only animals of this class which 

 use the tail as a weapon of defence ; and this, by being 

 armed along its ridge with hard and pointed spines, is 

 used to strike with, and, in the larger species, must be 

 a very dangerous part. Their skin is covered with 

 numerous small bucklers or shields ; and their mouth, 

 furnished with long and narrow teeth, appears like a 

 mighty gulf, sufficient to swallow an animal almost as 

 large as themselves. In its more congenial element, 

 the water, it has no foes capable of attacking it ; and if, 

 as it is said, the carnivorous quadrupeds will sometimes 

 assault the alligator, he avoids the encounter by making 

 for the water and, diving beneath, thus sets his pur- 

 suers at defiance. We must, however, recollect that 

 these monsters inflict wounds either in self-defence, or 

 when pressed by the calls of hunger ; but such is not 

 the case with the majority of the serpent tribe. Their 

 defence may be compared to the anger of a captious 

 man, who, from being by nature quarrelsome, takes 

 fire, and vents his spleen upon every one who comes in 

 his way. Those very large lizards, which both in 

 America and India are called guanas, although their bite 

 is not dangerous, can defend themselves most effectually. 

 The guana curls its tail towards its mouth when in dan- 

 ger, and lashes its enemy with it in a dreadful manner, 



