Montana Field Guide

EGGS:
This species is viviparous and does not lay eggs. Eggs develop internally and females give birth to live young. Broods include 2-15 young (typically 3-6), averaging about four (Lewis 1946, Pimentel 1959, Vitt 1973, Nussbaum et al. 1983, St. John 2002, Stebbins 2003).

HATCHLINGS:
Newly born young are about 2.0-3.0 cm (0.8-1.2 in) snout-vent length (SVL) and 7.5 cm (3 in) total length (TL) (Pimentel 1959, Vitt 1973, Nussbaum et al. 1983, Werner et al. 2004).

JUVENILES AND ADULTS:
The body is elongated, and the legs are short. The back is brown, tan, or gray to olive, yellow, or greenish. Juveniles have a broad reddish-tan stripe running the length of the back. The dark sides of the body are often checkered with small dark patches, and there is a distinctive dark patch around the eye (Stebbins 2003). 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, and revealing small granular scales when spread apart. Males have larger and broader triangular-shaped heads than do females. Adults are 7.0-10.0 cm (2.8-3.9 in) SVL and up to 20.0 cm (7.9 in) TL. No size dimorphism between the sexes, although sometimes within populations, females may be larger (Stewart 1985).

Body morphology (elongate body with short legs) and presence of a longitudinal fold of skin on each side of the body separates the Northern Alligator Lizard (Elgaria coerulea) from other native lizard species to Montana. Western Skink (Plestiodon skiltonianus) have a shiny appearance, distinct longitudinal stripes of brown, black, and golden-yellow, and a blue tail in juveniles and young adults. Greater Short-horned Lizard (Phrynosoma hernandesi) are flattened, widened through the body, and “prickly” in appearance. The pale bellies of Common Sagebrush Lizard (Sceloporus graciosus) and Western Fence Lizard (S. occidentalis) lack darkened edging that gives the belly a banded appearance, they sometimes have blue patches on the belly and throat. Both species feel rough when handled, due to the keeled scales (St. John 2002, Stebbins 2003). Only the Western Skink is broadly sympatric with the Northern Alligator Lizard in western Montana. The Western Fence Lizard is present at one locality (Sanders County) within the range of E. coerulea in Montana (Werner et al. 2004).

No information is currently available.

The Northern Alligator Lizard occurs in areas cooler and more humid than tolerated by most lizards, but it does require some sunny clearings. It is found in coastal stand communities of stabilized dunes, mixed coniferous forest, often in grassy grown-over areas at margins of woodlands and in clear cuts. They can also use areas near streams with riparian strips of Aspen (Populus tremuloides) or other tree and shrub species that can be dense, and in juniper-sagebrush and rabbitbrush habitats (Svihla 1942, Lais 1976, Stewart 1979, Nussbaum et al. 1983, Vindum and Arnold 1997, St. John 2002, Stebbins 2003). In these habitats it occurs on the ground often under downed wood and rocks, and in leaf and needle litter.

Habitat use in Montana has not been the subject of study, but records associated with encounters provide a sense of habitat requirements. Several observations of Northern Alligator Lizard have been made on south-facing slopes, in or at the margins of fine to coarse talus. Sometimes these sites have had little canopy cover, but more often there has been some cover of Douglas-fir (Pseudotsuga menziesii) and Ponderosa Pine (Pinus ponderosa). The understory contains a variety of shrubby species including Serviceberry (Amelanchier sp.), Ninebark (Physocarpus sp.), and Mock Orange (Philadelphus sp.) with a litter layer of dried leaves and conifer needles, and can be fairly close to streams (Place 1989, Werner and Reichel 1994, Hendricks and Reichel 1996a, Werner et al. 1998, Boundy 2001, Paul Hendricks, personal observation).

Adults and juveniles actively forage, albeit not widely and sometimes haltingly in a slow stalk or propelled snake-like movement with the legs folded at the sides (Nussbaum et al. 1983, Place 1989, St. John 2002). Hunting is mainly by sight, but some evidence suggests they can identify prey by odor (Cooper 1990) resulting in one reason for high rates of tongue-flicking. Arthropods form most of the diet, but slugs and earthworms are also taken. Other prey types include snails, spiders, millipedes, centipedes, and ticks. Individuals in captivity have eaten neonatal mice (Cooper 1990, 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. It is also frequently detected rustling through litter of dried leaves and needles or sunning in an exposed location. On the Washington coast, the body temperature ranged from 20 to 30 °C (68 to 86 °F) and correlated with substrate temperature. Males basked during the height of spermatogenesis. Basking may be especially important in high elevation populations.

The life history for this species has not been thoroughly studied. After emerging from winter hibernation, Northern Alligator Lizards are active during the day 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 1996a, Boundy 2001); however, the hibernacula in Montana are not described.

Home range size has not been reported, but adults in coastal Washington are gregarious in early spring and fall, concentrating in localized hibernation sites (Vitt 1973). At a coastal California location most animals were relatively sedentary, usually being recaptured within 10 m (32.8 ft) of initial capture site. Marked lizards were never found outside the 1.5 ha study plot (Stewart 1985).

There is little information on the predators of this species. 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.

Studies from other locations of Northern Alligator Lizards have documented mating in April and May in coastal Washington (Svihla 1942, Lewis 1946, Vitt 1973), and elsewhere in the Pacific Northwest (Nussbaum et al. 1983). Gestation is about three months, with a single brood of live young born in August-September in coastal California and Washington (Lewis 1946, Vitt 1973, Stewart 1985). Females reach sexual maturity between 32 to 44 months in northern California (Nussbaum et al. 1983, Stewart 1985, St. Johns 2002, Stebbins 2003) with larger females producing larger clutches and young (Pimentel 1959, Stewart 1979). No information is available from Montana on any aspect of the reproductive biology of this species.

Additionally, no information is available on the longevity of Northern Alligator Lizard, but late age of maturity and low fecundity suggest long life expectancy (Vitt 1973, Stewart 1985). Annual mortality in a coastal California population was 46% for all juvenile size classes and 27% for adults (Stewart 1985). Adult female survivorship exceeding that of adult males.

The following was taken from the Status and Conservation section for the Northern Alligator Lizard account in Maxell et al. 2009.

At the time the comprehensive summaries of amphibians and reptiles in Montana (Maxell et al. 2003, Werner et al. 2004) were published, there were 74 total records for Northern Alligator Lizard from six counties west of the Continental Divide, with records concentrated near the Idaho state line, and extending east to the western base of the Whitefish Range and west slope of the Mission Mountains. With so few records, the current status in Montana is largely uncertain. The Northern Alligator Lizard has not been documented in Glacier National Park (Marnell 1997) but has been reported south of there in the Mission Mountains on the east side of the Flathead Valley (Brunson and Demaree 1951, Werner et al. 1998a). There is also a noticeable absence of records between the lower Clark Fork River and the Flathead Valley, despite seemingly suitable habitat in that region. The eastern extent of the range in Montana is poorly defined. Because the Northern Alligator Lizard has not been the focus of life history or population studies in Montana, it is difficult to identify conservation needs. On the local scale, limited data from California and Washington indicate this species is relatively sedentary and gregarious (Vitt 1973, Stewart 1985). Thus, populations appear vulnerable to habitat fragmentation, especially where valley bottom habitat is developed or dramatically altered. Population density measurements are not available for Montana and are few overall; a two-year mark-recapture study at a coastal California site resulted in a mean monthly estimate of 142-167 lizards for the 1.5 ha study area, and an average density of 95-111 lizards when adjusted for juvenile mortality (Stewart 1985). In British Columbia, they may be locally abundant, but are usually distributed sparsely (Gregory and Campbell 1984). To summarize, risk factors relevant to the viability of populations of this species are likely to include habitat loss/fragmentation, fire, road and trail development, quarrying, river/stream impoundment, and use of pesticides and herbicides. However, perhaps the greatest risk to maintaining viable populations of Northern Alligator Lizard in Montana is the lack of baseline data on its distribution, status, habitat use, and basic biology (Maxell and Hokit 1999). These data are needed to monitor trends and recognize dramatic declines when and where they occur. No studies address or identify risk factors. The presence of Northern Alligator Lizard in “cut-over areas” indicates some degree of tolerance to canopy removal, so long as ground cover remains (Nussbaum et al. 1983). Some vegetative cover or talus appears to be desirable in areas where foraging occurs. Invasion of exotic weeds into occupied habitat has and continues to occur in western Montana, but it is unclear how associated habitat changes may affect populations. Use of chemical agents to control weed and insect pest infestations could depress populations of Northern Alligator Lizard, which feed on ground-dwelling arthropods. Several Northern Alligator Lizards died in the laboratory after they ate caterpillars of the cinnabar moth, an introduced pest control agent for controlling poisonous Tansy Ragweed (Senecio jacobaea), and there is a possibility that this exotic moth may have adverse effects on Northern Alligator Lizard populations (Nussbaum et al. 1983).