602 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1917. 



and the sharks at least have lithe and graceful forms, with lines as 

 finely molded as those of a clipper ship. The prejudice in this case 

 is based on the reputation which these fish have as "man-eaters." 

 As a matter of fact there are no man-eating sharks in the sense that 

 they generally or even frequently feed on human beings. There are 

 rare cases of men being injured or killed, and probably partially 

 devoured by one or several of the larger species of shark, but these 

 are mere infrequent accidents like 'the killing of children by hogs, 

 and from the standpoint of the character of their diet there is more 

 reason for eating shark meat than there is for eating pork. 



The food of sharks is in general like that of other carnivorous 

 fishes. There are some that feed on crabs, shrimps, and other bot- 

 tom-dwelling animals, such as are eaten by the cod and some of its 

 relatives, and some which confine themselves to a fish diet, like the 

 blue-fish and others. They are all habitually "clean" feeders, but 

 when hungry some of them will attack anything of suitable size. 



They are eaten in many parts of the world, frankly as sharks, and 

 considerable quantities of the moderate sized species enter the New 

 York market where most of them are sold fresh as "sturgeon," 

 "ocean or deep-water swordfish," or otherwise under the guise of 

 species more generally known to the public. 



Some sharks are solitary in their habits, or nearly so, but others, 

 particularly the smaller species, occur in great schools which range 

 over the sea and appear sporadically in the coastal waters at certain 

 seasons, when their rapacity is such as to cause great harm to the 

 fisheries through the destruction wrought on the common food fishes 

 and the injury inflicted on the fishermen's nets and lines. One of the 

 most common of these piratical little sharks is the spiny dogfish, 

 which has been on the market smoked and canned for about a year. 

 As there are several other sea and fresh-water fishes, and even a large 

 salamander bearing the name " dogfish," and as it is used opprobri- 

 ously by the fishermen, exasperated at their losses, the Bureau of 

 Fisheries changed its official name to grayfish, and it is known as 

 such in the market. 



The food qualities of the sharks vary somewhat with the species, 

 some having a strong and others a bland flavor. Their nutritive 

 value as shown by analysis, and their digestibility as tested by feed- 

 ing experiments, is about the same as that of other fishes and meats. 

 They differ from other fishes, from meats, and particularly from 

 poultry, by being entirely free of uric acid, and by possessing a much 

 higher content of urea and ammonia. These latter substances are 

 harmless to health and objectionable on esthetic grounds only if the 

 fish is not canned or cured promptly after removal from the water. 



The skates and rays are apparently an ancient offshoot of the shark 

 ancestral stem. They have become flattened in adaptation to a bot- 



