Flooding can have a disastrous effect on eastern fence lizard hatchling populations.
To attract mates and warn off other individuals, male eastern fence lizards do head bob displays, push ups, and puff themselves up. Head-bobs and push-ups are done in 4 to 5 second durations.
Communication Channels: visual
Perception Channels: visual ; tactile ; acoustic ; vibrations ; chemical
Eastern fence lizards are thriving due to the availability edge habitats and secondary growth around pine forests, their preferred habitat.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
After being laid, eggs double in size during embryonic development. Eggs hatch from June to September. Upon hatching, individuals are about half the size of adults. They tend to grow quickly in the first two months of life and are fully mature at 1 year.
Eastern fence lizards are not pests and do not have a negative effect on the human population. If individual lizards are harassed, they may bite.
Eastern fence lizards are used to help educate people about conservation and reptiles. Eastern fence lizards decrease insect and arachnid populations, which can be pest species in some areas.
Positive Impacts: research and education; controls pest population
Eastern fence lizards mainly feed on insects and are themselves prey for birds and other larger predators. They compete with other lizard species for their insect prey. Common parasites include chiggers and botflies.
Commensal/Parasitic Species:
Eastern fence lizards eat primarily insects and other arthropods, including ants (Formicidae), beetles (Coleoptera), weevils (Curculionidae), lady bugs Coccinellidae), spiders (Araneae), and centipedes (Chilopoda). They also sometimes eat snails (Gastropoda). Some plant matter like cheatgrass (Bromus tectorum) and needlegrass (Caproni stipa) is sometimes consumed. Females tend to eat more insects during the spring months, in order to save energy for egg-laying. Lizards generally forage twice daily.
Animal Foods: insects; terrestrial non-insect arthropods; mollusks
Plant Foods: leaves
Primary Diet: carnivore (Insectivore , Eats non-insect arthropods)
Eastern fence lizards range from mid New York south to mid Florida and northern part Texas and as far west as Colorado.
Subspecies include: southern fence lizards, S. u. undulatus, southern prairie lizards, S. u. consobrinus, White Sands prairie lizards, S. u. cowlesi, northern plateau lizards, S. u. elongatus, red-lipped prairie lizards, S. u. erythrocheilus, northern prairie lizards, S. u. garmani, northern fence lizards, S. u. hyacinthinus, and southern plateau lizards, S. u. tristichus.
Biogeographic Regions: nearctic (Native )
Eastern fence lizards are found in grasslands, shrublands, and the edges of pine or hardwood forests. Eastern fence lizards live under wood piles, logs, and rocks where they can be protected during the evening hours. During daylight hours eastern fence lizards can be found basking in the same areas in which they rest: on fences, logs, rock, and tree trunks.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: savanna or grassland ; forest
Lifespans of eastern fence lizards are not well understood, but researchers believe that they can live for more than 5 years, possibly averaging ages of 4 years. However, the majority of eastern fence lizards probably die soon after hatching.
Range lifespan
Status: captivity: 5 (high) years.
Average lifespan
Status: wild: 4 years.
Eastern fence lizards vary in color geographically, but are usually gray, brown or a rusty color. Males and females are similar in size. Individuals in northern populations (northern New York south to Maryland) are generally smaller than individuals in southern populations (northern Virginia south to northern Florida). This may be because southern populations have a longer warm season in which to eat and grow.
Males have a blue patch on the belly and throat. Average adult mass is 15 g, while adult total lengths range from 9 to 19 cm.
Average mass: 15 g.
Range length: 9 to 19 cm.
Other Physical Features: heterothermic
Sexual Dimorphism: sexes colored or patterned differently; male more colorful
Males with larger blue patches are more likely to be preyed on by birds. As a result, males have a high mortality rate during early spring when they are establishing mating territories. Females have a higher mortality rate during the period of egg-laying, because they are protecting their territory, making them more susceptible to predators. Larger lizard species, snakes, and domestic cats and dogs also eat eastern fence lizards. Eastern fence lizards are slower than other lizards, often giving predators. Eastern fence lizards are cryptically colored and can move quite rapidly when they are warm.
Known Predators:
Anti-predator Adaptations: cryptic
During the mating season, beginning in April, males flash their blue patches to attract females. Males also have anal glands that secrete a pheromone during and after breeding season to attract females. After mating males and females no longer associate. Males may seek other mating opportunities.
Mating System: polygynous
Mating occurs from April to August. Young females lay one clutch of 3 to 13 eggs. Older females lay 2 to 4 clutches per year. Eggs hatch from June to September. The eggs are laid below 3 to 7 cm of soil so that the moisture and temperature remain constant. It may take 10 weeks for the eggs to hatch after they have been deposited. The offspring reach maturity at 1 year of age.
Breeding interval: Young eastern fence lizards lay one clutch per year while older females can lay 2 to 4 clutches per year.
Breeding season: Breeding occurs from April to August.
Range number of offspring: 3 to 13.
Average gestation period: 8 weeks.
Range age at sexual or reproductive maturity (female): 1 to 2 years.
Range age at sexual or reproductive maturity (male): 1 to 2 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; sexual ; fertilization ; oviparous
Female eastern fence lizards increase body size if food is available, which is directly correlated to an increased clutch size. After laying her eggs females leave their young to fend for themselves.
Parental Investment: no parental involvement; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female)
The eastern fence lizard (Sceloporus undulatus) is a medium-sized species of lizard in the family Phrynosomatidae.[3] The species is found along forest edges, rock piles, and rotting logs or stumps in the eastern United States. It is sometimes referred to as the prairie lizard, fence swift, gray lizard, gravid lizard, northern fence lizard or pine lizard.[4] It is also referred to colloquially as the horn-billed lizard. One of its most notable behaviors is that of its escape behavior when encountering fire ants.
The generic name, Sceloporus, is derived from the Greek skelos/σκελος, meaning "leg", and the Latin porus, meaning "hole", referring to the enlarged femoral pores found in this genus of lizards. The specific name, undulatus, is Latin for "wave", referring to the transverse dark crossbars on the backs of these lizards.[5]
Until 2002, 10 subspecies of S. undulatus were recognized,[6] but re-evaluation showed paraphyly between the subspecies. These were reclassified as four distinct evolutionary species (the three new species being S. consobrinus, S. tristichus, and S. cowlesi). The narrowed redefinition of S. undulatus has been suggested to still contain two subspecies divided by the Appalachian Mountains. None currently hold formal recognition.[7] This variation can be partially attributed to the high nucleotide variation. One study found an average of 38 SNPs per kilobase of DNA.[8]
The following cladogram is based on Leaché and Reeder, 2002:[7]
Sceloporus undulatus species groupS. undulatus
The eastern fence lizard can grow from 4.0 to 7.5 inches (10 to 19 cm) in total length (including tail).[9] It is typically colored in shades of gray or brown, and has keeled scales, with a dark line running along the rear of the thigh. A female is usually gray and has a series of dark, wavy lines across her back. The belly is white with black flecks, with some pale blue on the throat and belly. The male is usually brown, and during the summer, has a more greenish-blue and black coloration on the sides of the belly and throat than the female. The young look like the females, but are darker and duller.
The lizards mostly inhabit sparsely wooded areas with ample sunlight, such as pine barrens with sandy or loose soil. They can be found basking atop of both natural and artificial structures including coarse woody debris, tree stumps, rock piles, sandy hills, dead logs, and fence posts. They are most active in the early morning sun when the ground has not been fully warmed up yet. They seek refuge under structures such as woodpiles, logs, and rocks for coverage and protection when it gets too hot and at night.[10]
This species has sexual dichromatism, which is a difference in coloration between the sexes. Males are blue and black on their ventral side. In some lizards, this coloration appears green or turquoise. In males, these patches assist intraspecific sex recognition and signaling. The size of patches correlates with the size of a lizard, and therefore may be a signal towards females or other antagonistic lizards.[11] Males are somewhat uniformly brown elsewhere with a reddish tinge.[12]
Females and juveniles are slightly colored blue and black on the ventral side or not at all. Their coloring is more complex, with "rows of dark brown or black chevrons set against a background of gray and brown."[12]
This sexual dichromatism is correlated to and somewhat regulated by plasma levels of testosterone in juveniles and adult females. Higher levels of testosterone support stronger blue and black ventral coloration.[12]
Male eastern fence lizards can also experience short-term color changes on their dorsal side and badge after exposure to temperature changes. The color of a lizard affects its social dominance or inferiority, camouflage, and self-regulation of temperature. Social dominance as a result of lizard color may exist because coloration would then possibly provide an honest indicator of lizard temperature and health.[13]
It is thought that sexual dimorphism and sexual differences in behavior may be due to differences in androgen concentration and receptor immunoreactivity.[14]
The eastern fence lizard is found in Alabama, Louisiana, Arkansas, Colorado, Georgia, North Carolina, South Carolina, West Virginia, Virginia, Indiana, Kentucky, Southern Illinois, Southern Indiana, Tennessee, Ohio, Pennsylvania, Maryland, Missouri, Mississippi, Delaware, northern Florida, southern Wyoming, northeastern Pennsylvania, southern New Jersey, and southeastern New York.[7] It prefers open woodland and the edges of forests.
There are some introduced populations of eastern fence lizards, the most well known in Staten Island, New York. In 1942, Carl Kauffeld released 29 of the lizards near Rossville where they still persist today in post oak-blackjack oak barrens.[15][16] This introduction was done so Kauffeld could have an easy source of food for the lizard-eating snakes at the Staten Island Zoo, as he would otherwise have to drive to the Pine Barrens to collect the lizards for the snakes.[17][18] There have also been sightings of the fence lizards in northern Pennsylvania and southern New York (in the Hudson Valley and Long Island), suggesting that their range may be expanding north.[19]
Despite its broad geographic distribution, these lizards tend to prefer temperatures that optimize their digestive performance. Their locomotive performance is optimal over a relatively broad range of body temperature.[20]
The eastern fence lizard has several adaptations to better survive in colder regions of its distribution, including larger eggs, more efficient embryonic development, and shorter incubation times. The larger egg sizes are not a result of greater maternal investment — even when forcibly made smaller, efficiency and incubation time were similar to the originally larger eggs.[21]
On the other hand, female lizards in southern regions produce second clutches more often, although their clutches are smaller than northern ones. The season at which eggs can incubate and lizards may be active is longer in the southern regions.[22]
The overall reproductive success of both northern and southern lizards are approximately equal, given that all else (i.e. body size) is equal.[22]
When climate conditions are stable, fence lizards prefer to sleep in the same site over short periods of time. The site selected is within the lizard's home range or territory.[23] When climate conditions are not stable, it has been found that some eastern fence lizards have been able to survive small frozen periods, and then return to normal after the period is over.[24]
The running speed of these lizards is not limited by their mechanical power output. As the slope of the terrain increases, running speed and stamina of lizards decreases. Eastern fence lizards run faster uphill than downhill at a fixed degree of incline or decline. Lizards with higher running speeds also have higher stamina in regard to time and distance.[25]
Male eastern fence lizards will establish a territory in the early spring, doing push-ups to flash their blue scales and deter other males.[26] Males will headbob more at males with smaller ventral patches, but aggressiveness is not affected by male patches.[11]
The size of a male's territory (home range area) is directly correlated with his body size. The territory of smaller males in their first breeding season tends to be smaller. Territories may overlap; about half of any given male's territory is shared by another male.[26] Within their territory, males cluster around the ranges of females, who are a limited resource. As such, the range and distribution of males is predominantly determined by the distribution of nearby females.[26]
Courting begins after female fence lizards encounter a male within his territory. Males express sexually dimorphic ventral abdominal coloration during courting. This coloration is used to attract mates, as more and brighter colors have been recorded to increase the likelihood of courtship.[27]
In 60% of instances where a female and male encountered each other, males displayed courting behaviors. Older and larger males tend to win contests with other males, and therefore gain access to any nearby females. Any contest victories or defeats did not affect a lizard's future location.[26] Larger bodied males are more likely to mate with multiple females.[28] Contests with other males and courtship towards females elevates plasma levels of corticosterone, an indicator of stress, in adult males.[26]
Feeding behaviors
Fence lizards are ambush, sit-and-wait, predators.[29] They are insectivores that typically eat arthropods such as ants and grasshoppers.[30] Studies have shown that eastern fence lizards display an ontogenetic shift in consumption of native and invasive prey. Although eastern fence lizards are an ant specialist, invasive imported red fire ants can pose a risk to young, smaller-bodied juveniles if they consume them, especially because young fence lizards are more common consumers of ants than adults.[31] It was found there was an increased consumption of fire adults in the adult life stage compared to earlier life stages.[31] These lizards are known to forage generally twice a day. Females will eat more during the breeding season for greater energy storage to help produce offspring.[32]
The female finds a suitable location to lay her eggs, usually in a rotting log or similarly damp area, and deposits them without any further parental care.[33] Young females will only produce one clutch of three to sixteen eggs, while a large female can produce up to four.[34] The eggs take approximately ten weeks to hatch and emerge near the end of summer. The young lizards grow quickly and are able to reproduce the next year.
Unfavorable nesting conditions can cause females to retain their eggs longer than they would have otherwise. This phenomenon is referred to as egg retention. Egg retention in the eastern fence lizard produces heavier eggs with more advanced embryos and with higher posthatching survival rate, but does not influence phenotype.[35]
Greater reproductive energy allocated to first clutches is common at higher latitudes, whereas more energy is dedicated to later clutches in lower latitudes.[36]
After the eggs are laid by a female, the development of the embryo and yolk within differ from that of birds, which has long been assumed to be identical. Instead, the process is more similar to snakes.
Strands form a vascularized network within the yolk sac cavity. The embryo and yolk sac cavity then progress through three distinct developmental stages.
In the first stage, endodermal cells develop and invade the nourishing yolk in order to digest it. They may clump within and begin filling the cavity.
In the second stage, the vasculature of the yolk sac produces blood vessels that expand throughout the cavity.
In the third stage, the cells organize themselves around the blood vessels. They can now more quickly and easily digest yolk. The products of digestion reach the embryo via release into blood vessels.[37]
The pressures of predation can select for a variety of escape tactics. In their natural habitat, these lizards encounter invasive ants, red imported fire ants (Solenopsis invicta), the bites of which threaten the lizards with envenomation and, possibly, reduced growth in juveniles. Fire ants also compete with eastern fence lizards for their nesting habitats and predate on their eggs. [38] These encounters can be dangerous and even lethal to the lizards. When attacked by these stinging fire ants, fence lizards twitch their bodies to throw off the attacking ants before fleeing.[39] The learning of these lizards after repeated exposure to fire ants has also been studied. Lizards that were more familiar or exposed to attacking fire ants tend to twitch more and flee sooner compared to lizards that were not exposed. This may also be an adaptive behavioral response induced by higher stress levels (and thus, elevated corticosteroids). However, exposure to fire ants did not increase the percentage of lizards that demonstrates escape behavior. Instead, those that had priorly shown escape behavior were more likely to show escape behavior earlier and more strongly. In other words, this behavior is not learned, but can be shaped if already present. The number of twitches performed by a lizard is also not affected by previous exposure. Juveniles, which are younger and smaller, flee more rapidly than adults in any encounter.[39] Furthermore, within the past 70 years, according to a study published in 2009, eastern fence lizards in certain regions have adapted to have longer legs and new behaviors to escape the red imported fire ant, which can kill the lizard in under a minute.[40]
Given the incubation period of the eggs, one study suggests that 61% of nests may be at risk of predation by these invasive fire ants. Nest choice and distance to the nearest fire ant mound did not significantly impact predation; thus, because there is little that eastern fence lizards can do to resist such predation on their eggs, there is conservation efforts toward stopping invasive species such as this fire ant.[38]
Eastern fence lizard at the Shawnee National Forest
Lizard at Douthat State Park camouflaging on wood
On a fence post
_with_turquoise_markings.jpg)
Underside of a male showing the turquoise markings
Eastern fence lizard eggs
The eastern fence lizard (Sceloporus undulatus) is a medium-sized species of lizard in the family Phrynosomatidae. The species is found along forest edges, rock piles, and rotting logs or stumps in the eastern United States. It is sometimes referred to as the prairie lizard, fence swift, gray lizard, gravid lizard, northern fence lizard or pine lizard. It is also referred to colloquially as the horn-billed lizard. One of its most notable behaviors is that of its escape behavior when encountering fire ants.
Sceloporus undulatus Sceloporus generoko animalia da. Narrastien barruko Phrynosomatidae familian sailkatuta dago.
Sceloporus undulatus Sceloporus generoko animalia da. Narrastien barruko Phrynosomatidae familian sailkatuta dago.
Sceloporus undulatus est une espèce de sauriens de la famille des Phrynosomatidae[1].
Cette espèce se rencontre :
Sceloporus undulatus est une espèce de lézards ovipares de taille moyenne que l'on trouve aux lisières des forêts, dans les tas de roches et les billes de bois ou dans les souches pourrissantes. Son aire de répartition s'étend depuis le Sud de l'État de New York, le New Jersey et la Pennsylvanie, les États du Sud-Est des États-Unis jusqu'aux Grandes Plaines et, au sud, jusqu'au Nord du Mexique.
Il peut mesurer 10 à 17 cm de long. Il est généralement de couleur grise ou brune, avec des écailles carénées avec une ligne sombre qui longe l'arrière de la cuisse. Les femelles sont généralement grises et ont une série de lignes ondulées noires à travers leur dos. Leur ventre est blanc avec des tâches noires. Ils sont légèrement bleu pâle sur la gorge et le ventre. Les mâles sont habituellement de couleur brune mais pendant l'été, ont beaucoup plus de couleur bleu-vert et noire sur les côtés du ventre et la gorge que la femelle. Les jeunes ressemblent aux femelles, mais sont plus foncés et plus ternes.
Il ressemble beaucoup au lézard des palissades mais en diffère légèrement par sa coloration et le fait qu'il vive dans une zone et un habitat totalement différents.
Ce sont des animaux diurnes et passent beaucoup de leur temps à se prélasser. Leur régime alimentaire se compose principalement d'insectes et d'araignées. Surpris, ils se précipitent vers un arbre à proximité, y grimpent sur une courte distance, puis se cachent de l'autre côté du tronc, se déplaçant autour pour rester du côté opposé de celui qui s'en approche.
Ils s'accouplent au printemps, et pondent de 3 à 16 œufs en fin de printemps ou au début de l'été. Les jeunes éclosent en été et en automne.
Ils peuvent faire de bons animaux familiers car certains sont très dociles, mais d'autres peuvent être très féroces, et sont mieux seuls.
Ils souffrent des attaques des fourmis de feu qui tentent de leur soulever les écailles leur ventre mou, et de lui injecter un venin neuromusculaire toxique qui les tuerait. Les lézards se sont adaptés par un allongement rapide de leurs pattes pour échapper plus rapidement aux fourmis qui peuvent les tuer en moins d'une minute.
Selon Reptarium Reptile Database (3 septembre 2014)[2] :
Les sous-espèces Sceloporus undulatus tristichus et Sceloporus undulatus edbelli ont finalement été élevées au rang d'espèce.
Le nom de l'espèce, undulatus, vient du latin undulatus, ondulé, qui fait référence aux barres dorsales de cette espèce[1]. Les sous-espèces sont nommées :
Sceloporus undulatus est une espèce de sauriens de la famille des Phrynosomatidae.
Lo sceloporo ondulato (Sceloporus undulatus - Bosc, 1801) è un rettile insettivoro arboreo o terragnolo. È diffuso nella pare settentrionale del Messico e in quella meridionale degli Stati Uniti (Virginia, Florida, e Nuovo Messico).
Tra le sottospecie riconosciute dello sceloporo ondulato risultano:
Lo sceloporo ondulato (Sceloporus undulatus - Bosc, 1801) è un rettile insettivoro arboreo o terragnolo. È diffuso nella pare settentrionale del Messico e in quella meridionale degli Stati Uniti (Virginia, Florida, e Nuovo Messico).
