A male collared lizard, Crotaphytus collaris, surveyed its
territory from atop a small boulder. I approached to get a
better look, but it moved to hide in a clump of grass. I
approached again, and it moved to another boulder, but here it
took a stand, doing pushups to signal that it was ready to
defend its territory. I had two immediate impressions. First of
all, this male was a dandy, brightly colored and ornately
patterned. Second, its slender body, long legs and enormous feet
clearly indicated that it was a runner. Several selective forces
influence the pattern and colors of collared lizards. Juveniles
and females are cryptically colored, and their colors and
textures vary from site to site, depending on the color of the
local soil and rocks. This selection is administered by a long
list of predators, including red-tailed hawks, Swainson's hawks,
northern harriers, Cooper's hawks, ravens, crows, kestrels, bull
snakes, pine snakes, black rat snakes, coachwhips and racers. An
experimental study demonstrated