Montana Field Guide

Northern Alligator Lizard - Elgaria coerulea

The body of the northern alligator lizard is elongate and the legs are short. The back is brown, tan, or gray to olive, yellow, or greenish. The dark sides of the body are often checkered with small darker patches. The belly scale rows are edged with a darker area giving the white to pale gray belly a banded appearance. There is a distinctive fold of skin running along each side of the body extending between the legs, revealing small granular scales when spread apart. Males have larger and broader triangular-shaped heads; juveniles have a broad reddish-tan stripe running the length of the back. Adults of E. c. principis are 7 to 10 centimeters snout-vent length (SVL) and up to 20 centimeters in total length; newly born young are about 2.5 to 3.0 centimeters snout-vent length.

The northern alligator lizard body is elongate and the legs are short. The back is brown, tan, or gray to olive, yellow, or greenish. The dark sides of the body are often checkered with small darker patches. The belly scale rows are edged with a darker area giving the white to pale gray belly a banded appearance. There is a distinctive fold of skin running along each side of the body extending between the legs, revealing small granular scales when spread apart. Males have larger and broader triangular-shaped heads; juveniles have a broad reddish-tan stripe running the length of the back. Adults of E. c. principis are 7 to 10 centimeters snout-vent length (SVL) and up to 20 centimeters in total length; newly born young are about 2.5 to 3.0 centimeters snout-vent length.

Montana Range

No information is currently available.

There is little specific information on habitat associations in Montana. Several observations have been made on south-facing slopes in fine to course talus, sometimes in the open, but often with some canopy cover of Douglas-fir, ponderosa pine, a variety of shrubby species (serviceberry, ninebark, mock orange), and a litter layer of dried leaves and conifer needles (Werner and Reichel 1994, Hendricks and Reichel 1996, Werner et al. 1998, Boundy 2001, P. Hendricks personal observation).

From other locations within the species' range, the northern alligator lizard occurs in areas more cool and humid than most lizards tolerate, but it also appears to require some sunny clearings. It is found in coniferous forest, often in grassy grown-over areas at the margins of woodlands, in clearcuts, sometimes near streams or in sagebrush habitats, along coasts sometimes far from trees or major cover, often associated with rock outcrops and talus in some regions, and frequenting areas around abandoned buildings (Lais 1976, Nussbaum et al. 1983, St. John 2002, Stebbins 2003).

An invertivore, northern alligator lizards feed on insects, ticks, spiders, centipedes, millipedes, slugs and snails (Nussbaum et al. 1983, St. John 2002, Stebbins 2003). There is no information on the food habits of this species in Montana.

Limited information is available for Montana. The northern alligator lizard is a secretive species, most often found under logs and rocks, although it is frequently detected rustling through litter of dried leaves and needles or sunning in an exposed location. The life history has not been thoroughly studied. Northern alligator lizards are active during the day, after emerging from winter hibernation, from April to September (Nussbaum et al. 1983, St. John 2002, Stebbins 2003). Animals have been found surface active in Montana from early April through September (Rodgers and Jellison 1942, Werner and Reichel 1994, Hendricks and Reichel 1996, Boundy 2001); hibernacula in Montana are not described. There is little information on the predators of this species, but they readily drop their tails, and tails have been found in stomachs of snakes (Nussbaum et al. 1983). There are no reports of predation on this species in Montana.

On the Washington coast body temperature ranged from 20 to 30 degrees C. and correlated with substrate temperature. Males basked during the height of spermatogenesis. Basking may be especially important in high elevation populations.

No information is available specific to Montana. Based upon information from other locations the species apparently mates in April and May. One litter per year is produced, with litter size varying depending on the geographic locality (3 to 8 in the Seattle, Washington area, and 2 to 6 on the central Oregon coast, with a mean of 4 in both localities). Young are born live in about three months after eggs are fertilized (June to September). Females reach sexual maturity in 32 to 44 months in northern California (Nussbaum et al. 1983, St. Johns 2002, Stebbins 2003).

No special management activities for northern alligator lizards are defined at this time; the little incidental survey data available indicate that western skinks may be locally abundant in some areas of extensive talus slopes in Montana (P. Hendricks personal observation), even though the range of this species in the state is restricted to the northwestern counties. Systematic surveys of appropriate habitats for this lizard are highly desirable to establish habitat associations and preferences, periods of activity, food habits, and relative abundances in Montana.