254 UNIVERSITY OF COLORADO STUDIES 



species, 300 to 400 mm. in length, in the University Lake at Boulder 

 both in November and the following March. Hibernating adults of 

 this species are often found in midwinter. One of the enemies of the 

 tiger salamander was found to be the snapping turtle, Chelydra 

 serpetitina (Linnaeus), which promptly seized and devoured large 

 larvae of Ambystoma tigrinum when placed in the same tank. The> 

 behavior of this turtle suggests a possible method of removal of the 

 young tiger salamanders from reservoirs in which that species has 

 become too abundant. 



Family Bufonidae 



Bufo boreas Baird and Girard 



Columbian Toad 



Tolland, 9,000 ft.. May, 1913 (429); Buena Vista, 8,500 ft., June 5-9, 1914 (459 and 

 460); Cottonwood Springs near Buena Vista, 9,000 ft., June 6, 1914 (489); Hortense 

 Hot Springs near Buena Vista, 8,500 ft., June 10, 1914 (490) ; near Alma, above io,ooo ft., 

 August, 1914 (491); Estes Park, July 31, 1904 (C.C); near Twin Lakes, Jime 7, 1914 

 (4Q2). 



This species was very abundant at Buena Vista in June, 1914. 

 At night the adults were found in numbers under the street lights 

 and in the grass near irrigation ditches. During the day few adults 

 were seen, but many juvenile specimens were collected about roadside 

 pools and in the short grass m the overflowed areas along Cottonwood 

 Creek and its tributaries. These juvenile specimens were feeding 

 actively during the middle of the day, although exposed to direct 

 sunlight, and individuals were observed frequently capturing spiders 

 and small Diptera among the grass stems. At Hortense Hot Springs 

 large numbers of juvenile individuals less than 30 mm. in length 

 were found about the overflow pool in water at 23° C. Following the 

 stream back from the overflow pool toward the springs the water 

 increased in temperature rapidly, the young toads continuing abun- 

 dant until the water was at 34° C. Above this point few toads were 

 seen, although one small individual was taken from water at 45° C. 

 quite near one of the springs. This toad was swimming very rapidly 

 at the time and may have been endeavoring to reach cooler water. 



