264 Shark and Company 



the embryo, carry a milky nutritive fluid which the embryo absorbs as 

 food. 



Some rays give birth to young fantastically large in comparison to 

 the mother. The late E. W. Gudger of the American Museum of Nat- 

 ural History reported that "the size of these young, flat, wide-pectoral 

 raylets, when ready for birth, is the thing that makes their parturition a 

 matter of seeming impossibility." 



Gudger reported the capture ofl^ Beaufort, North Carolina, of a ray 

 {Rhmoptera botiasus) 24 inches wide, which, "on being clubbed on the 

 head in the small boat to keep her quiet, gave birth to two young, each 

 8.5 in. long (tip of nose to end of ventral fin), and 13.5 in. wide." An- 

 other ray (Dasyatis sayi) from the same location was, Gudger reported, 

 "36 in. wide by 35 in. long. From her were obtained two young of about 

 equal size. The one measured was 14.75 in. wide and 5.75 in. long. In 

 addition the tail was 9.5 in. long." 



The female ray is able to accomplish the birth of such proportionally 

 huge young because the flat-bodied embryos are tightly rolled; they re- 

 semble a cigar in shape. At birth, its passage eased by the milky uterine 

 fluid in which it has been immersed, the ray pup leaves its mother's 

 body— and immediately unrolls in the sea and swims away. 



Family Potamotry gonidae— River Rays 

 So prevalent are Sting rays in fresh water that an entire family has 

 been allotted to them. These River rays are not so well known as their 

 salt-water kin because they often live in relatively unexplored jungle 

 rivers, particularly in Central and South America, and in parts of East 

 Asia and parts of Africa, where thev are said practically to carpet some 

 stretches of river bottom. While there are only a few identified species, 

 they can be extremely abundant where they are found. 



Typical of the wild and desolate areas where the River rays are found 

 are the nameless tributaries of the Rio Putumayo, where it snakes along 

 the Ecuador-Colombia border, hundreds of miles from the Pacific. There, 

 wrote explorer Rolf Blomberg in Buried Gold arid Anacondas,^ "is the 

 sting ray, whose habit is to lie hidden in the mud and sand on the river 

 bottoms; great care must be taken not to tread on it. It has a long tail with 

 poisonous serrated spines, and it is as skillful as a fencer in the use of 

 this weapon. An encounter with a sting ray is a painful and sometimes 

 really dangerous experience." 



Primitive South American Indians who have never seen the sea are 

 so familiar with the danger of stepping on a Sting ray that they drag 

 their feet when they wade in rivers. The Sting ray's poisonous barbs 



■6 Rolf Blomberg, Buried Gold and Anacondas (New York: Nelson, 1959). 



