228 FROM NORTH POLE TO EQUATOR. 



it never fails to tell of its discovery in loud cries. Thus it brings 

 under the notice of all the other creatures who share its home or 

 resting-place the unusual occurrence, enabling them either to find 

 out for themselves if there is really any danger, or to make good 

 their escape on the strength of its warning. Thus it discharges the 

 duties of a sentinel. Its friendly relations with the crocodile can 

 hardly be called mutual, for to credit the crocodile with friend- 

 ship is going rather far. Certainly the reptile treats the bird as 

 a harmless creature, but this is not out of any benevolence, 



Fig. 34. Crocodile and Crocodile-birds (Pluxianus cegyptius). 



but simply because he has a thorough knowledge and a correct 

 estimate of his partner. And as to the bird, it is at home on the 

 sand-banks where the crocodile is wont to rest, and has been from 

 its youth accustomed to the monster; it busies itself about him and 

 associates itself with him, as if he were the master and itself the 

 servant. Without hesitation it hops on his back as he rests; without 

 apprehension it approaches his gaping jaws to see if there be per- 

 chance a leech sucking his lips, or if there be some morsel of food 

 sticking between his teeth; and without misgiving it darts off with 

 either. All this the crocodile quietly allows, for doubtless he has 

 learned by experience that he cannot get at the ever watchful, agile, 

 and clever little rogue. I once saw a crocodile-bird having a meal 

 along with a screaming sea-eagle off a fish, which the latter had 



