312 3. IGUANIDM 



along the trails up Mt. Lowe and Mt. Wilson it is often 

 the cause of the leaf-rustling which startles the tenderfoot 

 into believing that he has heard the stealthy footfall of a 

 mountain lion. 



"It is in such canyons as the Arroyo Seco, Millard, Rubio, 

 Eaton, and Santa Anita, that the fence lizard is seen to best 

 advantage. For there the conditions seem most agreeable; 

 and where picnic parties come oftenest, the lizards seem to 

 become accustomed to human presence, and go about their 

 usual activities with little attention to anything but to one 

 another and to catching flies. They are very playful and 

 often start a game of tag, possibly some sort of preliminary 

 mating antics, and pursue one another at a lively rate over 

 the ground, springing nimbly from rock to rock, dashing up 

 tree trunks around which they whirl in dizzy spirals until 

 one actually drops to the ground and off into hiding in a 

 mass of dead leaves or a hollow log somewhere. Sometimes 

 this pursuit seems mere play, but at others it seems to be a 

 case of trespass. One pair of lizards will be found in the 

 same vicinity, that is, on a certain log or boulder, day after 

 day. If another ventures onto their domain, one of the 

 owners chases him off the premises. 



"Each individual, when at rest, frequently repeats a 

 curious motion, abruptly raising and depressing the front 

 part of the body, which means an alternate bending and 

 straightening of the front legs. This performance may be 

 repeated just the same when the lizard is being stalked by 

 a person with slip-noose, as when one lizard is paying atten- 

 tion to another. We have an idea that it may have to do 

 with gauging distances, as when one peers from side to side 

 to make sure of the distance of an object among the bushes 

 on a near hillside. Yet the lizard's brilliantly blue throat 

 and belly patches show up to best advantage during the 

 movements of the body, and the performance may be for 



