This whiptail was working hard at devouring some sort of insect, but still managed to pay enough attention to me to avoid letting me get a good shot of it.

Aspidoscelis sonorae is one of the unisexual whiptail species.

This species was placed in the genus Cnemidophorus until recently, so most reference books still use that name.

This might be Aspidoscelis exsanguis instead, but the iNaturalist consensus is A. sonorae. Unfortunately one of the more obvious ways to tell them apart involves examining the spots on the rump and top of the back legs, and this area is obscured by vegetation. Curse you, vegetation!

I'm not completely certain which species of whiptail this is. Adult Aspidoscelis sonorae have spots visible between the stripes, but the spots are typically not apparent in juveniles. This one was probably a juvenile, based on its relatively small size. But another similar-looking species of whiptail, Aspidoscelis uniparens, also lives in Madera Canyon. A. uniparens typically has some bluish or greenish color in the tail, which I'm not seeing here. Also, the hillside woodland habitat in which this gal was scurrying is a better match for A. sonorae; A. uniparens is typically found in more open areas. Both of these whiptail species are all-female (parthenogenetic), so I can be confident calling this lizard a gal.