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LIZARDS

Order Squamata
Suborder Lacertilia

Figure V-1, Appearing smooth and shiny, the body of the five-lined skink is covered with scales.Figure V-3, The northern coal skink rummages among its surroundings for insects. 

Above, L-R
Figure V-1, Appearing smooth and shiny, the body of the five-lined skink is covered with scales.
Figure V-3, The northern coal skink rummages among its surroundings for insects.

Figure V-4, The northern fence lizard could deposit two to four clutches of eggs after its first year.Figure V-2, This stream-laced, tree-lined ravine could provide the humid woodlands favored by most of Pennsylvania's lizards. 

Above, L-R
Figure V-4, The northern fence lizard could deposit two to four clutches of eggs after its first year.
Figure V-2, This stream-laced, tree-lined ravine could provide the humid woodlands favored by most of Pennsylvania's lizards.


Lizards make up the largest living group of reptiles, numbering about 3,000 worldwide. They are more predominant in warmer, drier areas, and in this country most are found in the southwest. Pennsylvania has four species from two genera and two families. They become more rare as they move northward. The lizards common to Pennsylvania are harmless.

Figure V-5
Snakes are closely related to lizards, from which they evolved. However, lizards have movable eyelids and external ear openings (See Figure V-5); snakes do not. Snakes also have no limbs, as do most lizards. (There also are some species of lizards in other parts of the country that do not have legs.) Lizards can swallow prey larger than might reasonably be expected. However, unlike the jaw of the snakes, the lower jaw bones of the lizards are firmly connected in front. This restricts the lizard's prey to smaller sizes than snakes can handle.

On the surface, salamanders (which are amphibians, not reptiles) may resemble lizards. However, there are several distinctly different features separating the two. The skin of lizards is scaly and dry, compared to the smooth, moist skin of salamanders. Lizards have clawed feet and external ear openings. The feet of salamanders are clawless (See Figure I-II) and these amphibians lack external ear openings.

Lizards for the most part are diurnal. They live in trees, on the ground and in burrows beneath the ground. They breed in the spring and most lay eggs following internal fertilization. Lizards possess the sensations of smell and taste much as we know them. Snakes do not. However, like snakes, many lizards are also able to use the tongue and Jacobson's organ to sample the air around them. (This organ is described in the opening section to the snakes.)

Many lizards, without apparent harm, can lose a tail to an attacker. An effective escape mechanism, special bone structures in a portion of the tail allow it to separate easily from the rest of the tail. This characteristic is called autotomy. In time, a new tail grows to replace the one lost, although its coloration is different.

Iguanid lizards

(Family Iguanidae)

Eastern fence lizardSceloporus undulatus

Only one species of this family is found in Pennsylvania. The iguanids are most predominant in warm, dry regions and more than 40 different species inhabit North America. This family is very large both in the numbers of species and in their physical size. Some species reach 72 inches or more. Some of the iguanids are egg layers. They are territorial in nature. Males defend their home stakes with an elaborate display of head bobbing and dramatic push-ups of the body, using the front legs. With mouth agape, they boldly inflate the chest and throat to present a menacing pose to any who would enter. Other displays, all designed to scare off intruders, are used as well.

Members of the family have five clawed toes on each leg. They also have a long tail.

Skinks

(Family Scincidae)

Northern coal skinkEumeces anthracinus anthracinus
Five-lined skinkEumeces fasciatus
Broadhead skinkEumeces laticeps

The skink family is a group of smooth, shiny, almost slippery lizards. The cylindrical body and tail are covered with smooth scales. This group is found on every continent with the exception of Antarctica. Over 1,200 species occur worldwide; three species are found in Pennsylvania. This family of reptiles is diurnal and likes a moist or damp area in which to live. Most are insect eaters. In some species, the female tends the eggs during the incubation period.

Species Descriptions

Northern Fence Lizard

Northern Fence LizardSceloporus undulatus hyacinthinus

General characteristics. The northern fence lizard belongs to a group of lizards commonly known as "spiny lizards." It is the only one of its genus in Pennsylvania. The northern fence lizard is not a large lizard. Adults range in size from four to seven inches, even though other members of its family in other parts of the world may reach 72 inches in length. It is diurnal and can be seen sunning itself, like many other reptiles. It spends a great amount of its time in trees where it hunts, rests and finds safety when frightened.

Identification. The northern fence lizard varies from gray to brown. Colors on the belly range from whitish to greenish blue to pale blue. There may be dark, wavy crossbars on the back, which are most evident normally on the female. The male has a blue patch near the base of the throat. The scales on the back of this lizard are keeled and pointed. They are jagged and rough to the touch, which explains its nickname, "spiny" lizard.

RangeRange. This reptile, territorial by nature, is located in roughly the southern two-thirds of Pennsylvania. Its range might extend a bit farther north within the Delaware River Basin. It can be found from New York to Georgia and west to Kansas and central Texas.

Habitat. The fence lizard defends its territory with an elaborate physical display that includes head-bobbing and open-mouthed gestures. Then, while appearing to do push-ups from its two front legs, the northern fence lizard inflates its chest and throat in an all-out effort to threaten an intruder.

Generally, the preferred habitat that it so vigorously defends is a sunny area of grassy or open woodland. It likes rotting logs and outcrops of rocks from where it can survey its domain. It often sits on a tree stump or fence, but usually is not far from a tree or wall where it can flee quickly to safety. When frightened, it scampers up a tree skirting to the opposite side where it remains motionless until it again feels safe. If caught from behind, the lizard quickly parts with its fragile tail. In time the broken appendage is replaced.

Reproduction. The northern fence lizard usually responds to the warming trend in April by seeking its mate. In some cases, mating does not occur until August. In its first year, the northern fence lizard lays one clutch of three to 13 eggs. In subsequent years, the female could deposit as many as two to four clutches. The eggs hatch from June to September and the young lizards measure about two inches as they break away from the egg.

Food. Beetles are a favorite food of the northern fence lizard and are eagerly sought. When beetles are unavailable, the lizard turns to other insects, spiders and even snails when it can locate them. Water is taken by the lizard from small deposits on rocks or droplets found on the leaves of nearby plants.

Northern Coal Skink

Northern Coal SkinkEumeces anthracinus anthracinus

General characteristics. A member of a single, very large family of skinks, the northern coal skink is difficult to distinguish from others of its genus. The coal skink does most of its foraging during daylight hours, as do other skinks. Adult sizes range from five to seven inches.

Identification. The body of the northern coal skink is brown. Two pairs of light stripes, each enclosing a dark band, extend from the neck onto the tail. There are no light lines on the head of the coal skink, which helps distinguish this skink from the two others found in the state. The breeding male might have a reddish head. The young have a blue tail, but otherwise are marked identically to the parents.

Figure V-6
RangeRange. In In Pennsylvania, the northern coal skink is known from the northcentral, a portion of the northwest, and one southwestern county. Its population is scattered and does not occur in large numbers anywhere in its range. It is also found in portions of New York, the Virginias and Kentucky.

Habitat. It prefers damp, moist woods, especially those with an abundance of leaf matter or loose stones. Springs, with their welcome supply of cool water, are favorite spots. Even so, this animal often occupies drier, more rocky open areas. When frightened, the coal skink quickly dives into water where it finds shelter beneath a convenient rock.

Reproduction. The northern coal skink mates in the spring to early summer. The female, which guards the eggs, deposits eight or nine of them in a small, protected depression in the ground. This usually occurs in June. They hatch after an incubation period of four to five weeks.

Food. Following the pattern of other skinks, the northern coal skink is insectivorous. It rummages among leaf litter and small stones in search of a variety of insects.

Five-lined Skink

Five-lined SkinkEumeces fasciatus

General characteristics. The five-lined skink is another of the state's smooth, shiny lizards. It is most comfortable in a temperature range of 78 to 85 degrees. These temperatures suit Pennsylvania's lizards and they are most active in this range. Like other skinks, the five-lined skink is diurnal and spends much of the day in search of food. It reaches an adult size that varies from five to just over seven inches.

Identification. This skink is brown to black with five broad, light stripes running the length of the body. In some adults, the pattern nearly fades completely with age. As the ground color becomes lighter, the stripes become darker. The tail of the juvenile is bright blue, turning gray as the skink grows older. During the breeding season, the head of the male is usually swollen and turns red-orange.

RangeRange. This skink is found from New England to Florida and west to Wisconsin and Texas. The five-lined skink inhabits about two-thirds of the state, generally south of a line drawn from Crawford County in the west to Bucks County in the east.

Habitat. It occasionally is seen in gardens or around homes, especially in damp areas, but it prefers humid woodlands. Decaying matter, abundant in most forests and even small woodlots, attracts the five-lined skink.

Reproduction. Warming temperatures in April and May signal the start of the breeding season. A clutch of four to 15 eggs is deposited in a nest, which is usually a small excavation in the damp earth. The female guards the eggs until they hatch in July to September. The young skinks measure two inches when they break out of their shells.

Food. Although considered terrestrial, the five-lined skink will climb a decayed snag in its forest home where it knows insects can be found in abundance. It consumes insect larvae, spiders, crustaceans, worms and even small mice, a diet perhaps more varied than that of some other skinks.

Figure V-7 

Broadhead Skink

Broadhead SkinkEumeces laticeps

Candidate Species

General characteristics. The broadhead skink is the largest of three skinks that inhabit Pennsylvania. Adult sizes range from just over six inches to a bit more than 12 inches, including the tail. The minimum length of an adult broadhead is barely less than the maximum size attained by Pennsylvania's other skinks. The broadhead skink is most active during the day, similar to others of the family. It has been placed on Pennsylvania's List of Candidate Species.

Identification. The outstanding characteristic of this skink is its head. On the male, it is large and gives the impression of having swollen cheeks. The body of this reptile is brown to olive brown and the breeding males are striking with their orange-red heads. There may be five light stripes down the body of both sexes during their early adult life, but these usually fade with age to become indistinguishable in the fully adult male. The juveniles are black with a bright blue tail. Five to seven brilliant yellow stripes are quite evident on the young, but patterns and colors fade with age and length.

RangeRange. Pennsylvania is on the extreme northern limit of this reptile's range. It is found only in the southeast corner of the state, and extends to central Florida. It ranges as far west as Kansas.

Habitat. Largely a woodland creature, the broadhead skink is the most arboreal of the state's skinks. It likes moist woods but also resides in open areas that provide adequate protection in the form of vegetative debris or other matter.

Reproduction. The broadhead skink seeks its mate during April or May. In May until July, the female deposits six to 16 eggs, usually in a small depression excavated beneath logs or leaves on the forest floor. The eggs hatch in June to August, after having been tended carefully by the female.

Food. Insects make up the major portion of the diet. A good climber, this skink hunts high in the trees in search of a meal, where it might also take advantage of cavities or small holes for temporary protection from unexpected cool temperatures.