14 DANGEROUS MARINE ANIMALS 



that had been caught in a coral crevice, a second shark moved into 

 the scene and, in one gulp, ripped out the belly of the first shark. 

 Within a few moments, the hapless shark was completely devoured 

 by additional members of the pack, which joined the killing. 



Sharks will frequently single out an individual in a crowd of 

 swimmers and will attack that one person, ignoring all others, in- 

 cluding those who attempt to rescue him. This phenomenon has 

 been observed on a number of occasions in various regions. On the 

 other hand, divers who have had the most experience with sharks 

 contend that "you cannot predict their actions". 



The danger of shark attacks is greatest in tropical and sub- 

 tropical seas, between 30° N. by 30° S. of the Equator (Fig. 1, 

 Bottom). Although temperate waters are generally considered to 

 be free of shark attacks, they are not completely exempt, as shark 

 attack records from both California and the eastern seaboard of 

 the United States clearly attest. Apparently, certain species of 

 man-eaters migrate periodically into cooler waters in quest of food, 

 and at such times attacks have occurred. Particularly dangerous 

 areas are Queensland, Australia, and South Africa. Despite the 

 lack of published scientific records, numerous attacks have also 

 been known to occur on the Pacific side of Panama. 



Most attacks have occurred when the temperature of the water 

 was greater than 70° F., although fatalities have taken place in 

 temperatures of 60° F., or less. The peak month of attacks is 

 January, and the period of greatest risk is between 1500 and 1600. 

 However, sharks feed at all hours, and particularly so at night. 



Species of Sharks Known to be Dangerous to Man: The sharks 

 believed to be of greatest concern to the diver are members of four 

 families. These families are listed according to what is believed to 

 be their order of greatest danger to man, namely : 



Isuridae — the Mackerel, or Man-eaters 

 Carcharhinidae — The Requiem Sharks 

 Carchariidae — the Sand Sharks 

 Sphyrnidae — the Hammerhead Sharks 

 Mackerel or Man-eater Shark Family (Isuridae) 



White Shark, Carcharodon carcharias (Linnaeus). (Fig. 2, Top). 

 This shark is reputed to be one of the most dangerous of its kind. 

 It is savage, aggressive, fast-swimming, and has been known to 

 attack boats. Numerous human attacks are accorded to this species. 

 The distinctive characters of this shark are the strongly lunate 

 caudal fin and large, coarsely serrate teeth. The color of the shark 



