YELLOW-BELLIED BACEB 643 



Western Yellow-bellied Racer. Coluber constrictor flaviventris (Say) 



Field characters. — Body long and slender; tail tapering to a fine point (fig. 62a); 

 scales of back all smooth (without keels) and placed in 17 rows. General coloration 

 above uniform olive brown, becoming greenish or bluish on sides of body and plain yellow 

 on whole of under surface. 



Occurrence. — Eesident at lower levels in western part of Yosemite region. Eecorded 

 from 3 to 6 miles east of Coulterville and from floor of Yosemite Valley. Lives chiefly 

 in grassland. 



The Yellow-bellied Racer, often known as Blue Racer, is less common 

 in the Yosemite section than is its striped relative. The present species 

 is essentially an inhabitant of grasslands or meadows and the scarcity of 

 this sort of habitat in the region is no doubt the factor which limits its 

 numbers. Our local specimens, three in number, were all obtained in 

 grassy places. 



The Yellow-bellied Racer is closely related to the Black Snake of the 

 eastern United States, and like that species has a rather aggressive dispo- 

 sition. When come upon, a Yellow-bellied Racer will first endeavor to 

 escape, and it is able to travel at surprising speed. But if cornered or 

 if pinned down under a stick or a person's shoe it will usually turn upon, 

 and endeavor to bite, its captor. This action though somewhat terrifying 

 to the average person is without serious consequences. The Racer has no 

 venom, and the most it can do is to puncture the skin on a person's finger 

 and perhaps cause a little bleeding. 



Valley Gopher Snake. Pituophis catenifer heermanni (Hallowell) 



Field characters. — Size variable, often large; body always relatively stout, but tail 

 tapering slenderly to a point. Scales on back ridged or keeled, and in 29 or more 

 rows. Ground color of body ocher yellow, marked along back with many ' saddle-marks ' 

 of dark brown, and with smaller dark spots along sides. (See pi. 59a.) When first 

 approached often lies motionless on ground; then glides off to nearest safety refuge; if 

 cornered, is likely to ' show fight ' by hissing and striking. 



Occurrence. — Fairly common in the Lower and Upper Sonoran zones and lower part 

 of Transition Zone on west side of Sierra Nevada. Recorded from Snelling and Pleasant 

 Valley eastward to floor of Yosemite Valley. Lives in grasslands and along road 

 margins; rarely or never goes into water or up into bushes or trees. Usually solitary. 



The Valley Gopher Snake, sometimes called "bull snake," is fairly 

 common in the western foothill district of the Yosemite region, and is 

 likely to be seen in any of the grasslands or along any of the dusty road- 

 ways up to 4000 feet altitude. 



The general run of gopher snakes to be found in the Yosemite region 

 will probably exceed in average size the rattlesnakes now found there. 



