Scincella lateralisGround Skink, Little Brown Skink

Geographic Range

Ground skinks (Scincella lateralis) are found throughout the eastern and central-eastern United States, as well as in northern Mexico. They are found in Arkansas, Alabama, Georgia, Louisiana, and Florida, except the Tampa Bay area. Ground skinks also range throughout the Carolinas, Tennessee, and Kentucky, excluding Louisville. They inhabit Virginia, east of the mountain ranges. Ground skinks are also found in the southern parts of Indiana, Illinois, Missouri, and southeastern Kansas. They inhabit southern and southeastern Texas, continuing south into the coastal plain of Mexico. (Evans, 1959; Hammerson, 2007; Hutchins, et al., 2003)

Habitat

Ground skinks are found in the Coastal Plain and Piedmont geographic provinces in the United States. They are found in humid, deciduous forests. They are also abundant in aquatic and semi-aquatic habitats, such as streams and pond edges. Ground skinks are ground dwellers; they are known to live in loose soil, leaf litter, and under decaying logs. During colder months, ground skinks go underground, deep into the soil. In urban and suburban areas, ground skinks inhabit vacant lots or the sides of buildings. No specific elevation has been recorded other than lower elevations. (Gibbons, et al., 2009; Hammerson, 2007; Mitchell, 1994; Wilson, 1995)

Physical Description

Ground skinks have dorsa that are light tan or golden brown and their abdomens are white or yellow. The color of their tails is light brown to gray with a brown to black lateral stripe. Ground skinks have smooth, shiny scales and a cylindrical body shape. They have conical heads with long tails and short legs. Adult female heads are larger (4.4 mm) than males (4.0 mm). Males have tails with an average length of 63.7 mm, while females average 55.6 mm. Both females and males have a snout-vent length of 57 mm. The total length of ground skinks is an average of 146 mm. There is no sexual difference in the color or pattern of ground skinks. Both sexes can drop their tails on command and regenerate them.

Juvenile ground skinks are bronze-colored with black specks on their bodies, tails and the dorsal side of their heads. At the tip of their tails, the black specks are more abundant and there are distinct dark strips on their heads going toward the tip of their tails. The average body length of hatchlings is 18 to 21 mm and, including their tails, they measure 50 to 53 mm. (Formanowicz Jr, et al., 1990; Gibbons, et al., 2009; Hutchins, et al., 2003; Minton, 2001; Mitchell, 1994; Wilson, 1995)

  • Sexual Dimorphism
  • female larger
  • Range length
    75 to 146 mm
    2.95 to 5.75 in

Development

Eggs hatch about 22 days after being laid. Hatching occurs in the late summer, during July and August. The average mass of ground skink hatchlings is 0.13 g and the average total length of hatchlings is 50 to 53 mm, 18 to 21 mm of that being their body length. Flewelling and Parker (2015) reported that both oxygen and temperature can affect the size of embryo and juvenile skink growth. After one year, ground skinks reach their adult lengths and become sexually mature. Like all lizards, these skinks exhibit indeterminate growth. (Flewelling and Parker, 2015; Minton, 2001; Mitchell, 1994)

Reproduction

Ground skinks breed between April and July. During those months, males will mate with females in their same home range. Males use chemical cues by flicking their tongues to find a potential mate. If there is competition, males will bite one another to establish dominance and determine which one will breed with the female. Larger males are more successful in breeding with females than smaller males. This species is known to be polygynandrous, meaning both males and females have multiple mates. (Mitchell, 1994)

After mating, males will depart and find other females to mate with. After females lays their eggs in a safe nesting spot, they will leave them. Females normally lay 2 to 3 eggs (range 1 to 6) in decaying wood or moist soil. The average egg size is 1.3 mm and females may lay up to 4 clutches per year, about 3 to 4 weeks apart. The gestation period is about 22 days. Both sexes reach maturity at age 1. The young are independent upon hatching. (Becker and Paulissen, 2012; Mitchell, 1994)

  • Breeding interval
    Breeding occurs every 3 to 4 weeks during the summer months
  • Breeding season
    Mating occurs in late April through July
  • Range number of offspring
    1 to 6
  • Average number of offspring
    2-3
  • Average gestation period
    22 days
  • Average time to independence
    0 minutes
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

Male have no parental investment after mating with females. After females lay their eggs in a safe nesting area, they do not guard them. Multiple female ground skinks may lay their eggs in the same nest; a single nest may contain as many as 60 eggs. Young are independent upon hatching. (Becker and Paulissen, 2012; Mitchell, 1994)

  • Parental Investment
  • pre-hatching/birth
    • provisioning
      • female

Lifespan/Longevity

On average, ground skinks can live in the wild for up to two years, but some individuals can live up to four years in the wild. In captivity, they typically live up to two years and six months. (Mitchell, 1994; Snider and Bowler, 1992)

  • Average lifespan
    Status: wild
    4 years
  • Average lifespan
    Status: wild
    2 years
  • Average lifespan
    Status: captivity
    2.5 years

Behavior

Ground skinks are terricolous but can be partially fossorial. Because they are diurnal, they spend most of the day basking in the sun and crawl through leaf litter. They generally do not climb. During the coldest months of winter, they will hibernate underground. In the southern parts of their range, they may remain active year-round.

As soon as ground skinks emerge from hibernation, mating season begins. Male ground skinks use tongue-flicking to pick up chemical cues and find potential female mates. Because they are sedentary animals, they do not have to travel far to find mates. To find their prey, ground skinks use visual cues.

To avoid predation, these animals can drop their tail, a behavior known as autotomy. However, Formanowicz et al. (1990) reported a behavioral complication. Once skinks drop their tails, they are more prone to predation. There is a marked drop in their escape speed (a decrease from 38 to 28 cm/second) and the distance they are willing to move when fleeing a risk (152 cm with tail, 9 cm without tail). The laboratory measure of activity (number of times that they switch positions per hour) also was lower in skinks without a tail by a factor of nearly 3. (Evans, 1959; Formanowicz Jr, et al., 1990; Townsend, et al., 1999)

Home Range

Ground skinks have average home ranges of 52 m^2 for males and 14 m^2 for females. They move around several times a week in the process of searching for food and potential mates. They use a technique called spatial learning, which allows ground skinks to enhance their knowledge of the area in which they live. This improves their chances of escaping from predators when fleeing. They do not defend a territory. (Paulissen, 2008)

Communication and Perception

Ground skinks use a combination of visual and auditory cues to find the opposite sex. Males collect chemical signals on their tongues; these chemicals allow them to locate nearby females. Ground skink males use a receptive sensory organ called the vomeronasal organ located on the roof of the mouth. This organ transmits signals to the brain, which helps males distinguish the sexually receptive and non-receptive females. During their breeding season, males are more aggressive towards other males. Ground skinks use visual and chemical stimuli to hunting their prey. Ground skinks primarily hunt using visual cues; if a potential prey item is out of sight, ground skinks can use tongue-flicking to pick up chemical trails. (Evans, 1959; Townsend, et al., 1999)

Food Habits

Ground skinks are generalists, consuming small invertebrates such as termites (Order Isoptera), millipedes (Order Diplopoda), wood roaches (Parcoblatta pensylvanica), ants (Family Formicidae), wood-boring beetles (Family Buprestidae), lepidopteran larvae and various arthropods and isopods. Adult ground skinks forage every 2 to 3 days, while juveniles consume food every other day. To find prey, ground skinks uses their sense of smell to find prey, which may be found underground. Their diet tends to change with the season, and depending on what arthropod prey items are present. (Mitchell, 1994; Wilson, 1995)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods

Predation

Ground skinks are preyed on by many snakes, such as common scarlet kingsnakes (Lampropeltis elapsoides), copperheads (Agkistrodon contortrix), and ringneck snakes (Diadophis punctatus). They are also eaten by wolf spiders (family Lycosidae), eastern bluebirds (Sialia sialis), and barred owls (Strix varia). Many other species of birds and small mammals also eat ground skinks. The typical way to escape from these predators is to run beneath leaves, logs, or other objects to hide. Ground skinks are also known to run into standing water and swim to the other side to get away from predators. If ground skinks are caught in a bad situation with a predator, they can drop their tails to try and escape from the predator. Their tails normally grow back in three to four months. They do not hide in trees. (Mitchell, 1994; Snider and Bowler, 1992)

Ecosystem Roles

Ground skinks are predators of small arthropods and isopods, and wood cockroaches (Parcoblatta pensylvanica). They are preyed on by many snake species.

Common protozoans found in ground skinks are intranuclear coccidians (Isospora manchacensis). These protozoans produce oocysts but are not harmful to ground skinks. Trematode parasites include Brachycoelium calamandrae and Mesocoelium americanum. Cestode parasites include Cylindrotaenia american, Cystiecercus, and Oochoristica eumecis. Nematode parasites include Cosmocercoides variabilis, Physaloptera squamata, Oswaldocruzia pipiens, Thubunaea squamata, and Thubunaea leiolopismae and unidentified larvae from the family Acuariidae. Ixodes scapilaris is a tick parasite found on ground skinks. According to McAllister et al. (2014), all of these parasites were found on ground skinks in Arkansas and Oklahoma. (Atkinson and Ayaia, 1987; McAllister, et al., 2014)

Commensal/Parasitic Species
  • Trematode (Brachycoelium salamandrae)
  • Trematode (Mesocoelium americanum)
  • Cestode (Cylindrotaenia americana)
  • Cestode (Cysticercus)
  • Cestode (Oochoristica eumecis)
  • Nematode (larva from Family Acuariidae)
  • Nematode (Cosmocercoides variabilis)
  • Nematode (Oswaldocruzia pipiens)
  • Nematode (Physaloptera squamata)
  • Nematode (Thubunaea leiolopismae)
  • Tick (Ixodes scapularis)
  • Protozoan (Isospora manchacensis)

Economic Importance for Humans: Positive

There are no positive economic impacts of ground skinks on humans.

Economic Importance for Humans: Negative

There are no negative economic impacts of ground skinks on humans.

Conservation Status

According to the IUCN Red List, ground skinks are considered a species of "Least Concern." The US Federal list as well as the CITES and State of Michigan lists have no special status for ground skinks. At the northern end of their range, some states do list them as protected. Illinois and New Jersey list ground skinks as a species of "Special Concern."

In 2016, New Jersey listed ground skink as a species of "Special Concern" due to habitat loss. In Mason and Menard counties, Illinois, ground skinks are listed as close to extinction because these populations are so isolated.

At the species level, there are no recommended conservation efforts for ground skinks. In New Jersey, conservation efforts are limited to requesting that members of the public report the date and location of any sightings of the species. Regarding the two counties in Illinois, there are no efforts in place to prevent the extinction of these populations. (Axtell and Bryant, 2006; Hammerson, 2007; Miller, 2016)

Contributors

Shanell Piercy (author), Radford University, Lauren Burroughs (editor), Radford University, Layne DiBuono (editor), Radford University, Lindsey Lee (editor), Radford University, Karen Powers (editor), Radford University, Galen Burrell (editor).

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

indeterminate growth

Animals with indeterminate growth continue to grow throughout their lives.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

terrestrial

Living on the ground.

urban

living in cities and large towns, landscapes dominated by human structures and activity.

visual

uses sight to communicate

References

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