112 BULLETIN 17 5, UNITED STATES NATIONAL MUSEUM 



Wooster (1925, p. 58) gives the following note: "The bull snake is a 

 much more effective ratter than most cats, and a good-sized one about 

 the barn pays for itself many times over, provided it does not have 

 access to the chicken nests, for it eats eggs and sometimes small 

 chickens." 



Guthrie (1926, p. 180) also stresses the value of this snake to agri- 

 culture. He gives the number of eggs laid as 13 to 19 and describes 

 and figures the development of the embryo. 



The food habits of sayi were studied in the laboratory by Hisaw and 

 Gloyd, who observed about 40 snakes of this form under conditions 

 made as normal as possible. Their paper (1926, p. 200) may be briefly 

 summarized as follows: "The bull snake kills its larger prey by con- 

 striction. Smaller and weaker animals are simply swallowed alive." 

 The prey is swallowed head first. "The bull snake is also an active and 

 efficient burrower and apparently is able to capture burrowing rodents 

 in their subterranean tunnels . . . When a snake attacks a small animal 

 in a narrow space . . . instead of employing its coils in the usual 

 manner, it attempts to compress its prey against one of the walls of its 

 confine . . . The power of sight of the bull snake is apparently some- 

 what limited. Though used in capturing the prey, it is not essential. 

 A snake is very sensitive to contact stimuli, and in the dark recognizes 

 prey very readily by this means. If, when in the act of kilUng a 

 victim by use of the coils, another animal comes in contact with the 

 snake's body, it is at once pressed against the side of the cage or con- 

 stricted by another series of loops. A single snake has been known to 

 kill as many as three half-grown rats in this way at one time. It was 

 also observed that the bull snake has a cyclic activity which includes 

 feeding, fasting, and moulting. This is apparently repeated about 

 every thii'ty days." By comparing the average weight of the food 

 eaten with the average weight of small mammals in its natural 

 habitat, it was estimated that an adult snake could consume twelve 

 adult pocket gophers or their equivalent in smaller rodents durings its 

 six months of activity. 



Morse (1927, p. 71) relates watching a bull snake kill a pocket 

 gopher and then drag it into a burrow to devour it. 



Another note on feeding habits is given by Linsdale (1927, p. 79) 

 as follows: "A large bull snake was eating rabbits in a nest on the 

 lower part of the bluff on April 25, 1925. The snake was coiled over 

 the nest to prevent the escape of the rabbits and had one of the young 

 mammals in its jaws." 



Gloyd (1928, p. 125) describes the hatching on September 18 of 

 6 eggs from a nest of 16 laid on July 4. The young snakes shed their 

 skins ten days later, but no food was taken until, at the age of nine 

 weeks, infant rats were swallowed. 



