268 Shark and Company 



removal. Along both edges of the underside of the stinger run two 

 deep grooves. Within the grooves flows the venomous secretion, whose 

 composition, chemically speaking, is little understood. There is no doubt 

 today— as there once was— that venom is secreted by the stingers. But 

 there is debate as to how this venom is injected into the Sting ray's 

 victim. 



In his Living Fishes of the World,'' Earl S, Herald, curator of the 

 Steinhart Aquarium of the CaUfornia Academy of Sciences, tells of a 

 study of more than 4,000 California Round Sting rays (Urolophus halleri). 

 The study showed that 45 per cent of the Sting rays had lost their 

 sheaths— and venom glands. "The larger and older the Sting Ray is, the 

 greater is the possibility of its having lost the venom glands and pro- 

 tective sheath," Herald wrote. "This explains why some people who 

 have been stabbed by Sting Ray spines have received only mechanical 

 injury without venom." 



Herald's findings do not agree with those of Dr. Bruce W. Halstead, 

 a physician who is director of the World Life Research Institute and who 

 was an instructor in tropical medicine at the U.S. Naval Medical School. 



Discussing the grooves of the stingers, Halstead writes in his Dan- 

 gerous Marine Anirrmls:^ 



If these grooves are carefully examined, it will be observed that they contain 

 a strip of soft, spongy, grayish tissue extending throughout the length of the 

 grooves. The bulk of the venom is produced by this tissue in the grooves, 

 although lesser amounts are believed to be produced by other portions of the 

 integumentary sheath, and in certain specialized areas of the skin on the tail 

 which lies adjacent to the spine. These grooves serve to protect the soft delicate 

 glandular tissue which lies within them, and even though all of the integu- 

 mentary sheath may be worn away, the venom-producing tissue continues to 

 remain within these grooves. Thus, a perfectly clean-looking spine can still be 

 venomous. 



Venomous or not, Sting ray wounds are inevitably painful, dangerous 

 —and surprisingly common. Halstead estimates that about 1,500 Sting 

 ray attacks are reported in the United States each year. Most victims 

 are attacked after stepping on a Sting ray lying partially hidden in the 

 mud near shore. If Sting rays are believed to be around, the safest way 

 to walk into the water is while shuffling your feet. In this way you 

 not only eliminate the possibility of stepping down on a Sting ray, you 

 also drive them away by stirring up the bottom. 



Sting ray poison produces excruciating pain and even paralysis. Pierre 



" Earl S. Herald, Living Fishes of the World (Garden City, N. Y.: Doubleday, 

 1961). 



* Bruce W. Halstead, Dangerous Marine Anmials (Cambridge, Md.; Cornell Mari- 

 time Press, 1959) . 



