California Herps

a web page by Don Roberson
Think of a very hot place. Lots of sun, stunted short dry grass, howling wind, patches of bare baked sand. That's Pixley National Wildlife Refuge, Tulare County, California (above). That remote site is one of the very few places in the world to see the endangered Blunt-nosed Leopard Lizard. This lizard would be special any time but for a brief time in early summer, the otherwise sandy-colored male turns into a bright orange caricature lizard, like a child's toy in its garish pattern. Few see this incredible brute, perhaps because he lives in the netherworld below ground most of the time. He emerges to defend his ground, seek mates, and devour prey during the hottest days of summer.
This is one kick-ass lizard. It is large as California lizards go; it is wary and very fast (it can even run bipedal if needed); and it is beautiful. Ordinarily the complex back pattern is exquisite even on the dullest examples, but these few bright orange males are astonishing. I had no idea they existed in this color until we encountered one, thanks to the efforts of Pam Williams & Steve Laymon, wildlife biologists studying the vertebrates of Pixley. It was the most impressive lizard I've seen in California.

Blunt-nosed Leopard Lizard Gambelia sila is one of three species of Leopard Lizard in n. Mexico and sw. United States, and one of a dozen species in the family Crotaphytidae [collared & leopard lizards]. All are fast, agile, long-limbed and long-tailed carnivores, dining primarily on smaller lizards and grasshoppers. When first encountered above ground, these leopard lizards held a pose with tail raised in an arch (above), as if ready to run at an instant. These are two different individuals (above & left) showing the typical pattern when not in full breeding condition. Small yellow blotches on the sides suggest immaturity (Pam Williams, in litt.). The dorsal pattern is a complex mosaic of spots, interspersed with pale cross-bars on the back. The back pattern reminds me of the dorsal pattern on the huge Whale Shark.

Blunt-nosed Leopard Lizard's color patterns are adapted to their habitats, and over the species' range in California there is wide variation within the paler to darker continuum. Many examples of this can be seen on Gary Nafis's great website on California herps.

Blunt-nosed Leopard Lizard is a California endemic. It was once widespread across the San Joaquin Valley but most of its habitat has been developed to agriculture and only isolated fragments remain. There is no population estimate, but a multi-year study on the Elkorn Plain (a stronghold) recorded 1078 lizards during their project (Germano & Williams 2005). The worldwide population may not be much higher. Many of the fragmented populations no longer have corridors of access to other populations, and one wonders about the eventual genetic effect of in-breeding. There is also concern about the impact of global warming on this and other lizards that require a specific temperature zone for foraging.

Blunt-nosed Leopard Lizards require rodent burrows for shade and predator protection. During the summer they are never far from a burrow, and in the winter they spend half-a-year underground. At Pixley NWR those burrows are provided by California Ground-Squirrels and Heermann's Kangaroo-Rats. We also encountered two other lizard species using burrows on the refuge: Coast (Blainville's) Horned Lizard Phrynosoma blainvillii (=Anota coronatum; below left; see fn1) and Common Side-blotched Lizard Uta stansburiana (below right).

Blunt-nosed Leopard Lizard is closely related to the more widespread Long-nosed Leopard Lizard G. wislizenii of eastern California and the Great Basin. [A third species, Cope's Leopard Lizard G. copeii, resides primarily in Baja California.] I've encountered Long-nosed Leopard Lizard a couple of times in the Death Valley area, and here are some comparative photos of the two species (below). At one time Blunt-nosed and Long-nosed were said to interbred in the upper Cuyama Valley, Ventura Co., but that habitat is now degraded; their ranges may no longer meet. A recent study in Ballanger Canyon, upper Cuyama Valley, found only pure Blunt-noseds (P. Williams, pers. comm.).
Long-nosed Leopard Lizard also brightens in color during breeding season. Gravid females get extensive orange spots and blotches. The photos below compare gravid females (i.e., those ready to lay eggs). The Long-nosed shown is very bright, but Blunt-noses can get a lot brighter than the female I photo'd (whose orange spots are reduced in size). You can see differences in shape of the head/length of nose in this comparison.
Long-nosed Leopard Lizard was my favorite California lizard before I visited Pixley. Rita and I had seen a Blunt-nosed in the Kettleman Hills of w. Fresno County, back in April 1991, but that lizard was not in breeding condition. Seeing this one at Pixley was a superb event. Given the beauty and cockiness of this male, and recognizing its status as Endangered and difficult to find, Blunt-nosed Leopard Lizard is now my choice for "California's best lizard."

The prime habitat at Pixley NWR for Blunt-nosed Leopard Lizard is not open to the public. Access to the refuge is limited to a short walking trail to an overlook of winter wetlands there. Blunt-nosed Leopard Lizard occurs in Carrizo Plains National Monument, where it can be found along the edge of Temblor Range [my friend John Sullivan saw his there]. There is a lot more information at Gary Nafis's California herps web site.

My visit with Rita Carratello to Pixley NWR on 13 June 2010 was arranged almost a year in advance, and we were just lucky that conditions were good and the wildlife biologists had 'staked out' a couple of active burrows for us.

Photos: All photos of Blunt-nosed Leopard Lizard were taken 13 June 2010 at Pixley NWR, Tulare Co., California [as were the horned lizaed & side-blotched lizard]. The first Long-nosed Leopard Lizard was photographed at Big Sandy Spring, Death Valley NP, Inyo Co., in June 1987. The gravid female Long-nosed Leopard Lizard was photographed at Saline Valley, Death Valley NP, Inyo Co., on 27 May 1978. All photos © Don Roberson, all rights reserved.

Literature cited:

  • Germano, D.G., and D.F. Williams. 2005. Population ecology of Blunt-nosed Leopard Lizard in high elevation foothill habitat. J. Herpetology 39: 1–18.

footnote 1: regarding Coast Horned Lizard — some recent research suggests that the population in Baja California is distinct and it bears the nominate name, cononatus, making our lizard blainvillii ("Blainville's Horned Lizard). There is also a proposal to change the genus, which gives us Phrynosoma blainvillii for our lizard, which had been known as Anota coronatum. The official lists have not yet sorted this all out.

  page created 18–20 June 2010  
all text & photos © Don Roberson, except as otherwise indicated; all rights reserved