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.
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.
- Habitat Regions
- terrestrial
- Terrestrial Biomes
- forest
- scrub forest
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.
- Other Physical Features
- ectothermic
- bilateral symmetry
- Sexual Dimorphism
- female larger
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.
- Development - Life Cycle
- indeterminate growth
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.
- Mating System
- polygynandrous (promiscuous)
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.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- sexual
- fertilization
- oviparous
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.
- Parental Investment
-
pre-hatching/birth
-
provisioning
- female
-
provisioning
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.
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.
- Key Behaviors
- terricolous
- fossorial
- diurnal
- motile
- sedentary
- hibernation
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.
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.
- Other Communication Modes
- pheromones
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.
- Primary Diet
-
carnivore
- insectivore
- eats non-insect arthropods
- 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.
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.
- 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.
Additional Links
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), Special Projects.
- 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.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- terrestrial
-
Living on the ground.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- scrub forest
-
scrub forests develop in areas that experience dry seasons.
- urban
-
living in cities and large towns, landscapes dominated by human structures and activity.
- suburban
-
living in residential areas on the outskirts of large cities or towns.
- riparian
-
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- 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.
- indeterminate growth
-
Animals with indeterminate growth continue to grow throughout their lives.
- polygynandrous
-
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- 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).
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- fossorial
-
Referring to a burrowing life-style or behavior, specialized for digging or burrowing.
- diurnal
-
- active during the day, 2. lasting for one day.
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- 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.
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- chemical
-
uses smells or other chemicals to communicate
- pheromones
-
chemicals released into air or water that are detected by and responded to by other animals of the same species
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- chemical
-
uses smells or other chemicals to communicate
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
References
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