Prairie skink (Plestiodon septentrionalis)

Description

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Prairie skink fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Prairie skink description

The prairie skink (Plestiodon septentrionalis), sometimes called the black-banded skink ⁽³⁾, is a highly secretive North American reptile ⁽⁴⁾. This species can be identified by its olive-brown or grey colouration ⁽⁴⁾, with alternating stripes of light olive to black ⁽⁴⁾. These stripes extend from the skink’s smooth, shiny body onto its tail ⁽²⁾. 

The underparts of the prairie skink, including its belly, chest, chin, throat, and the soles of its feet, are typically cream or pale yellow ⁽⁴⁾. The limbs tend to be darker above than below ⁽⁴⁾. The tail comprises about half the total length of the prairie skink, and the female is larger than the male ⁽⁴⁾. The juvenile prairie skink exhibits a bright blue tail ⁽²⁾. 

Two subspecies of prairie skink are recognised: the northern prairie skink (Plestiodon septentrionalis septentrionalis) and the southern prairie skink (Plestiodon septentrionalis obtusirostris) ⁽⁵⁾. The southern subspecies can be distinguished from the northern subspecies by its smaller size and by the absence of, or greatly reduced, mid-dorsal markings ⁽²⁾.

Also known as

northern prairie skink.

Synonyms

Eumeces septentrionalis.

Size

Total length: 13.3 - 22.4 cm ⁽²⁾

Southern subspecies total length: 12.5 - 17.8 cm ⁽²⁾

Prairie skink biology

For seven months of the year, the prairie skink take refuge underground, when the air temperature becomes too cold to ensure its survival. It locates or excavates a burrow, where it will hibernate for several months, using stored body fat as its only means of energy. The prairie skink emerges from hibernation in the spring, usually sometime between late April and early May ⁽⁴⁾. 

The male prairie skink emerges first and begins to prepare for the breeding season. The jaws and throat of the male skink take on a bright orange colouration, which is at its most vibrant at the start of the breeding season. The prairie skink continues to breed throughout the spring and early summer. During courtship, the male shows interest in a female by arching his tail and gently nudging and biting the female’s torso. This display may continue for up to 15 minutes, after which copulation then takes place ⁽⁴⁾. 

The pregnant female digs a shallow nest site in an area of loose, moist soil in preparation for her eggs ⁽¹⁾. After a gestation period of about 40 days ⁽⁴⁾, the female prairie skink lays a clutch of 4 to 18 eggs, with larger females laying bigger clutches ⁽⁵⁾. During incubation, the female is able to sense subtle alterations in humidity levels, and will move the eggs around the nest site, rolling them with her nose, or using her mouth or tail. After an incubation period of about 30 days, the hatchlings begin to emerge. At this time, the female will leave the nest and the young are on their own ⁽⁴⁾. The young continue to grow at a rate of about one millimetre per day ⁽⁴⁾ and reach sexual maturity in two years ⁽⁵⁾. 

Outside of the breeding season, the prairie skink spends most of its time under cover, becoming more active from mid-morning to mid-afternoon when temperatures increase ⁽⁴⁾. This species feeds on a variety of prey, including spiders, snails, insects and small lizards ⁽⁵⁾. Cannibalism has also been noted, with adults eating juveniles ⁽⁴⁾. 

When threatened by a predator, the prairie skink has an unusual escape mechanism. It will present its tail and shake it vigorously, allowing the predator to grab hold of the tail. When it does, the tail drops off, enabling the skink to scurry for cover. After dropping the tail, the wound quickly heals and a new tail begins to grow ⁽⁴⁾.

Prairie skink range

The prairie skink is endemic to North America ⁽¹⁾, where it ranges from southern Manitoba, Canada, to central Texas in the United States ⁽³⁾. 

The northern subspecies of the prairie skink occurs from western Wisconsin and Minnesota to Kansas, with an isolated population in southern Manitoba. The southern prairie skink ranges from east-central Texas to south-central Kansas, with another isolated population in the far south of Texas ⁽²⁾.

Prairie skink habitat

The primary habitat of the prairie skink, as its name suggest, is the prairies of North America ⁽³⁾. However, it can also be found in a variety of other habitats, with soil type being the main factor in its distribution ⁽⁴⁾. 

The prairie skink typically occupies areas of soft loamy sands (a mix of sand, silt and clay) ⁽⁴⁾, loose soil, and gravel ⁽²⁾, commonly taking up dwelling in sand hills and dunes ⁽⁴⁾. This species can tolerate moist or dry conditions ⁽³⁾. 

The prairie skink is highly opportunistic, and will take cover under a variety of natural and manmade structures, from large stones to wooden boards ⁽³⁾. The prairie skink will often find or create a shallow burrow for itself ⁽²⁾.

Prairie skink status

The prairie skink is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Prairie skink threats

The primary threat to the prairie skink is human interference to its habitat ⁽⁴⁾. The prairie skink’s native prairies are being fragmented and lost due to cultivation ⁽⁶⁾ and the development of housing areas, roadways, and factories, as well as fire suppression and the overabundance of grazing cattle. As a result of these threats, the flora of prairies is changing, with an increase in forested areas and exotic species, both of which can change the soil makeup. As this reptile cannot fulfill its normal life cycles without sandy soils, it is unable to survive in these encroaching forests ⁽⁴⁾.

Prairie skink conservation

Conservation of the prairie skink centres on the preservation of its habitat ⁽¹⁾. Many organizations have been established with the aim of protecting the biological and genetic diversity of the flora and fauna of North American prairies ⁽⁷⁾. This species is also found in many protected areas within its range ⁽¹⁾. 

The prairie skink receives various conservation designations throughout the U.S. and Canada, ranging from ‘Secure’ to ‘Critically Imperiled’, affording different levels of protection ⁽⁸⁾.

Find out more

Find out more about the prairie skink:

• NatureNorth - Biology of the northern prairie skink:
  http://www.naturenorth.com/summer/creature/skink/skink2.html

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Glossary

Endemic

A species or taxonomic group that is only found in one particular country or geographic area.

Genetic diversity

The variety of genes within a particular species, population or breed causing differences in morphology, physiology and behaviour.

Gestation

The state of being pregnant; the period from conception to birth.

Hibernation

A winter survival strategy in which the animal passes the winter in a resting state. This period of inactivity is characterised by specific biological and biochemical changes including lowered blood pressure and respiration rate. In reptiles, this is also known as brumation.

Home range

The area occupied by an animal during routine activities, which is not actively defended.

Incubation

The act of incubating eggs, that is, keeping them warm so that development is possible.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

References

1. IUCN Red List (August, 2011)
   http://www.iucnredlist.org/
2. Conant, R. and Collins, J.T. (1998) A Field Guide to Reptiles and Amphibians, Eastern/Central North America. Houghton Mifflin, New York.
3. Clarke, R. (1955) Observations on Eumeces s. septentrionalis in Kansas. Herpetologica, 11: 161-164.
4. NatureNorth - Biology of the northern prairie skink (August, 2011)
   http://www.naturenorth.com/summer/creature/skink/skink2.html
5. Somma, L. and Cochran, P.A. (1989) Bibliography and subject index of the prairie skink, Eumeces septentrionalis (Baird) (Saura: Scincidae). Great Basin Naturalist, 49: 525-534.
6. COSEWIC - Prairie skink (August, 2011)
   http://www.cosewic.gc.ca/eng/sct1/searchdetail_e.cfm?id=282&StartRow=1&boxStatus=All&boxTaxonomic=All&location=All&change=All&board=All&commonName=prairie%20skink&scienceName=&returnFlag=0&Page=1
7. Missouri Prairie Foundation (August, 2011)
   http://www.moprairie.org/
8. NatureServe Explorer (August, 2011)
   http://www.natureserve.org/explorer/