204 FAUNA OF WESTERN AUSTRALIA 



sometimes seen unattended by pilots, when those fish 

 accompany it, the number is always two ; and this fact is 

 so well known that the native draughtsmen invariably 

 depict this number in their representations of the shark — 

 an object they are very fond of graving on the rocks of the 

 coasts. 



While off one the islands, noted on the chart as Rat 

 Island, one of these monsters glided slowly under the 

 boat. The appearance of all fish in the depths of the sea 

 is deceptive to the eye ; but the size of this shark was 

 remarked by all the fishermen as being enormous. It was 

 accompanied by the usual pair of pilots, one swimming 

 close to the snout, the other near the right side. 



Neither book nor naturalist that I have yet met with 

 has given a satisfactory explanation of the object of the 

 attendance of these pilots on the shark, and I have none 

 to offer. On this west coast of Australia I never saw a 

 shark without its attendant scouts — if scouts they are. 

 They seem to guide, or warn, the shark in some way, but I 

 could never discover proof that they really do so. The 

 pilots are sometimes seen without the shark, but the latter 

 is probably lurking near at hand on such occasions. At 

 any rate the pilots never go in shoals, large or small, in 

 Australian waters. Four or five is the greatest number 

 that I have ever seen together ; but when a large number of 

 sharks are assembled in one spot, each seems to be 

 accompanied by its pair of attendants. This refers to the 

 common blue and white sharks only, the basking-shark 

 and the smaller sharks never having pilot-fish with them. 

 That some mutual benefit follows the association of 

 creatures so incongruous in general habits and organisa- 

 tion is certain, otherwise the pilot-fish would not be safe 

 in the company of the shark, for the latter often snaps at 

 very small prey. I have actually seen them seizing smaller 

 fish than the pilot, and one which I saw captured had more 

 than a hundred small fish in its stomach, not one of which 

 exceeded five inches in length. 



Regarding the species of sharks in this sea, I am pretty 

 sure that there are many accidental visitors in addition to 



