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Canadian Herpetological Society Société d'Herpétologie du Canada |
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Northern Prairie Skink
Plestiodon septentrionalis
Family: Scincidae
The subspecies of Prairie Skink that occurs in Canada is the Northern Prairie Skink (Plestiodon septentrionalis septentrionalis).
COSEWIC status:- Special Concern
- Special Concern
- Least Concern
Description
The Prairie Skink is a smooth, slender lizard that can grow to ~20 cm in total length, but most individuals are much smaller. Prairie Skinks are brown to gray with four light-coloured stripes down the back, and the belly is light gray. Hatchlings are 5–6 cm in total length and have bright-blue tails; the bright blue colouration fades with age. Males have a bright orange chin and jaw during the breeding season.
Similar Species
No other lizards are native to Manitoba. Salamanders have a similar body shape but lack the claws, scales, and external ear openings of lizards.
Distribution
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In Canada, the Prairie Skink is found only in Manitoba, where it occurs in two small areas in the southwest part of the province: the Carberry Sandhills and a small area of the Lauder Sandhills. These Canadian populations are isolated from those in the United States by a distance of 150 km. The Northern Prairie Skink subspecies is found from Manitoba south to Kansas while the southern subspecies extends from Kansas south to Texas.
Habitat
The Prairie Skink is associated with mixed-grass prairies and savannas, and in Canada it is limited to open areas with sandy soils. Though it may be more common on south- or west-facing slopes, the species uses edges of deciduous and mixed-wood forest and has been documented to move through both forest types. During the winter months, individuals burrow in sandy soils to depths of up to 140 cm to avoid freezing temperatures. Prairie Skinks spend their active season near the hibernation site. They have small home ranges, and some individuals have been observed to stay within areas as small as 30 m over a four-year period. Individuals occasionally make larger movements (over 500 m), but these are uncommon. Female Prairie Skinks lay eggs in a nest excavated under cover or in a small burrow; they may nest communally, although individual nests are more common.
Biology
In Canada, the Prairie Skink hibernates during the winter and is active from mid- to late-April until late September. Prairie Skinks breed in May and early June, and females lay 1–18 eggs (~5 eggs on average) from late June to early July. Females remain with the eggs throughout incubation and will move them around by mouth to ensure they experience optimal thermal and moisture conditions. The eggs typically hatch in mid-August, and individuals reach maturity at 1–3 years of age. Little information is available on the lifespan of this species, but most reproducing adults are 3–6 years of age and individuals can live for at least seven years in the wild. Prairie Skinks eat a wide variety of invertebrates, such as crickets, grasshoppers, and spiders. Common predators include a variety of birds, mammals, and snakes, including American Kestrels and Plains Hog-nosed Snakes. As a defensive strategy, individuals may autotomize (drop) their tail to distract a predator; tail autotomy is particularly common among juveniles. Although the tail will grow back over time, it is energetically costly and may negatively affect growth and survival.
Threats
Historical loss of mixed-grass prairie habitat through cultivation practices may be the most limiting factor for this species in Canada, including more recent conversion of habitat to potato fields. Fire suppression has resulted in grassland progressing to aspen parkland forest, a habitat less suitable to this species. Additional threats that are degrading or eliminating grassland habitat include development and invasive plant species such as Leafy Spurge.