Biology of Skinks

Skink Basics

The northern prairie skink (Plestiodon septentrionalis) is a reptile. It belongs to a group, or family, of lizards known as the Scincidae (pronounced “skink-i-day”). Skinks are the most diverse group of lizards, with 1200 species worldwide. The northern prairie skink is one of 27 species of skinks in North America. As a group skinks have a typical lizard body form, but have short, indistinct necks, short legs and long tapering tails. Males of most species display orange or red markings during the breeding season. In many North American skinks juveniles have a bright blue tail.


The prairie skink is a small, slender lizard, olive-brown or grayish in colour with alternating light and dark stripes running the length of its body. The belly is light grey. Adult skinks can grow to a length of about 20 cm (about 8 inches), head to tail, but half of that length is usually its tail. Females tend to be a bit larger than males. Juvenile skinks have bright blue tails. The blue colour fades as they reach adult size. During the breeding season adult males develop orange colouration on their heads and throats.

Names Explained

The scientific name for the northern prairie skink is Plestiodon septentrionalis (recently changed from Eumeces septentrionalis). Plestiodon is thought to derive from the Greek: "pleistos", meaning "most, the most or the greatest", "odontos" is from the Greek, meaning "teeth" (thanks to John White for helping out with the etymology). The species name "septentrionalis" is latin for "of the north". So they are the "most-toothed skinks of the north". The etymology of scientific names, their underlying meaning, often seems more art than science, except perhaps to the person that coined the name in the first place.

The word "skink" comes from Latin "scincus" or Greek "skinkos", which was the common name for a of kind of lizard common in Asia and North Africa. The common name for this lizard, "northern prairie skink", is pretty obvious: a skink that lives in northern grassland regions. There is, in fact, a southern prairie skink, too. The two are considered to be subspecies, or different varieties, of the prairie skink. Plestiodon septentrionalis septentrionalis is the northern subspecies (our Manitoba Skink) while Plestiodon septentrionalis obtusirostris (= blunt nose) is the southern prairie skink. The ranges of these two critters are given in the Biogeography section.


Habitat for skinks in Manitoba seems to be limited to areas of mixed-grass prairie in sandy soils. (For some background see Manitoba's Mixed-grass Prairie in In the open grasslands the sun can reach and warm the ground. Skinks need this extra warmth as part of their habitat. Many of the native grasses have a tufted growth form (bunch grasses) that provide dense cover for skinks and habitat for the skinks main prey, crickets and spiders. Areas with very sandy soils are necessary for the skinks to construct nests and burrows, especially for their winter hibernation. In human populated areas artificial cover objects, like boards or plywood, are sought-after cover for skinks. Under such cover objects temperatures are favourable, not too hot or too cool, and they often harbour the insects skinks feed on.


Skinks, like most reptiles, are "cold-blooded", or more properly "ectothermic". They don't produce their own body heat like "warm-blooded", or endothermic, animals: birds and mammals. Being an ectotherm means you don't have to use up most of the energy you get in your food just to make heat, so skinks can live on far less food than a comparably sized bird or mammal. But it doesn't mean you have to give up being active when temperatures are cool. Like most reptiles, skinks can maintain a fairly warm body temperature (22 - 35 C) during day time by basking or seeking out warmer microhabitats. They can maintain a constant temperature during sunny weather by selecting spots to either warm or cool themselves. In cool, cloudy weather skinks will be less active. At night they will retreat to burrows or bury themselves under the sand and let their body temperatures cool to that of the ground.


For about 7 months of each year, from late September to late April, skinks must avoid being active on the ground surface; it's just too cold for them. They are not freeze tolerant like some of Manitoba's frogs (see Frozen Alive in If a skink freezes, it dies. Skinks must find burrows, or dig their own, where they can spend winter below the frost line, which may be 1 m deep in southern Manitoba. This is one reason they are limited to areas with sandy soils where it is easy for them to dig to depths that will not freeze. As ectotherms they let their body temperatures drop to the surroundings in their burrows and require little food to survive their 7 months of cold storage. The energy they store as body fat is enough for them to survive their hibernation.

Life History

There is an excellent account of skink reproduction in the NatureNorth article: The Northern Prairie Skink, by Errol Bredin. Here is a quick synopsis.

In Manitoba skinks emerge from hibernation in late April and early May. Mating occurs in May or June. In late June or early July females lay 4 to 18 eggs in shallow nests they dig, usually under some form of cover. The female stays with her eggs until they hatch, in about 30 days, usually in early August. Then the hatchlings are abandoned to make their own way in the world.

At 2 years of age skinks are full grown and can breed. The life span for skinks is not well documented, but Errol Bredin recaptured an adult after 5 years, suggesting that some can live for up to 7 years.


Prairie skinks are secretive creatures spending most of their time hidden under some form of cover. They tend to stay near the ground and don't climb up shrubs or onto rocks. At night they retreat into burrows to avoid the coolest temperatures and nocturnal predators. Skinks are active from mid-morning to mid-afternoon when temperatures are warmer. Spring and early summer, their mating period, is when they are most active and most likely to be seen by people. Their home ranges, the total area they live in, are quite small, often less than 1000 square metres (1/10 ha or 1/4 acre). Skinks aren't territorial so the home ranges of numerous skinks can overlap. They tend to seek out areas with a south or west facing slope, sites that will get more sun and stay warmer longer.


Skinks can occur in surprising numbers in areas of good habitat. One researcher in the US estimated that skink densities ranged from 50 to 200 individuals per hectare; that's up to 1 skink for every 50 square metres. Population densities for skinks in Manitoba haven't been estimated yet.

Food Habits

Skinks are active predators, hunting and eating a variety of insects and small invertebrates. Crickets and spiders seem to be their favourite prey, but they will eat grasshoppers and a variety of other insects. Cannibalism by adults on juveniles has been reported.

Skinks as Food

Skinks are food for a variety of larger predators. Snakes, in particular the western hognose snake, will eat skinks. Kestrels, crows and other predatory birds likely take their share, and mammals like raccoons and skunks likely eat them, too. Large frogs or toads would certainly be able to eat juvenile skinks.

A skink's main defense against being eaten is to stay under cover as much as possible, but they have another trick they rely on. One characteristic shared by most skink species is the ability to shed and regrow their tails. If a predator attacks a skink and grabs it by the tail, the tail will break off and continue to thrash around distracting the predator long enough for the skink to make its escape. The surviving skink then grows a new tail.

Additional Information

For more detailed information on the biology and conservation status of the northern prairie skink in Manitoba download the COSEWIC Status Report on the Northern Prairie Skink (1.3 MB PDF).

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