Identification
The greater short-horned lizard (Phrynosoma hernandesi) is often mistaken for its close relative the pigmy short-horned lizard (Phrynosoma douglasii) which has the same basic body type consisting of small pointed scales around the head and back. Until recent mitochondrial DNA evidence, P. hernandesi was considered to be the same species as P. douglasii. They are now considered distinct species with the Pygmy Horned Lizard (P. douglasii) occupying the northwest portion of the United States and extreme southern British Columbia. When placed together the two are easily distinguished at full size, the pygmy horned lizard being much smaller. P. hernandesi is a highly variable species with different geographic populations exhibiting differences in color, pattern and size with some authorities describing five subspecies. The short-horned lizard ranges in size from 2-5 inches from snout to vent (4.5-12.4 centimeters) in length and is a flat-bodied, squat lizard with short spines crowning the head. They have a snub-nosed profile and short legs. The trunk is fringed by one row of pointed scales, while the belly scales are smooth. The color is gray, yellowish, or reddish-brown, and there are two rows of large dark spots on the back. When threatened or aggressive, their colors become more intense.
Females grow to larger sizes than males: females average some 7 cm (about 2.75 inches) from snout to vent (with a maximum total length of about 15 cm) and weigh about 18 g, whereas males have an SVL of only about 5 cm and weigh on the average about 10 g.
Read more about this topic: Greater Short-horned Lizard