Herpetology

Gekkonidae- Gecko Lizard

Habitat: warm climates around the world Size: They range from 1.6 to 60 cm (0.64 to 24 inches) Communication: are unique among lizards in their vocalizations. They use chirping sounds in social interactions with other geckos. Appearance: Geckos occur in various patterns and colors, and are among the most colorful lizards in the world. Some species can change colour and may be lighter in colour at night. Unique traits: Most geckos cannot blink, but they often lick their eyes to keep them clean and moist. They have a fixed lens within each iris that enlarges in darkness to let in more light. Nocturnal species have an excellent night vision; their color vision is 350 times more sensitive than human color vision so they rely on it for hunting. Unlike most lizards, geckos are usually nocturnal. Most gecko species can lose their tails in defense, a process called autotomy. Many species are well known for their specialised toe pads that enable them to climb smooth and vertical surfaces, and even cross indoor ceilings with ease. Geckos are well-known to people who live in warm regions of the world, where several species of geckos make their home inside human habitations. Geckos are polyphyodonts and able to replace each of their 100 teeth every 3 to 4 months. Skin: All geckos shed their skin at fairly regular intervals, with species differing in timing and method. Reproduction: Some species are parthenogenetic, which means the female is capable of reproducing without copulating with a male. This improves the gecko's ability to spread to new islands. The gecko's mating call sounds like a shortened bird chirping which attracts males, when they are nearby. Body heat: Like other reptiles, geckos are ectothermic, producing very little metabolic heat. Essentially a gecko's body temperature is dependent on its environment. Also, in order to accomplish their main functions—such as locomotion, feeding, reproduction, etc.—geckos must have a relatively elevated temperature  Polychridae- Anoles

Scincidae- skinks

Lifestyle: Skinks are generally carnivorous and in particular insectivorous. Appearance: Skinks look like wall lizards, but most species have no pronounced neck, and their legs are relatively small; several genera (e.g., Typhlosaurus) have no limbs at all. Other genera, such as Neoseps, have reduced limbs and with fewer than five toes on each foot. Can be determined by the black stripes running down its sides. Size: some Skinks are quite small, but most skinks are medium sized (snout-to-vent lengths around 12 cm or 4.7 in) Unique Characteristics: In species that have reduced to no limbs, their locomotion resembles that of snakes more than that of lizards with well-developed limbs. As a general rule, the longer the digits, the more arboreal the species is likely to be. Most species of skinks have long, tapering tails they can shed if predators grab onto them. Such species generally can regenerate the lost part of a tail, though imperfectly. Species with stumpy tails have no special regenerative abilities. Name: The word "skink" comes from classical Greek skinkos, a name that referred to various specific lizards of the region. Behavior: A trait apparent in nearly all species of skink is a love of digging and burrowing. Most spend their time under ground where they are mostly safe from predators, sometimes even digging out tunnels for easy navigation. They also use their tongues to sniff the air and track their prey. When they encounter their prey, they chase it down until they corner it or manage to land a bite and then swallow it whole Habitat: species occur in a variety of habitats worldwide, apart from boreal and polar regions. Various species occur in ecosystems ranging from deserts and mountains to grasslands. More species are terrestrial or fossorial (burrowing) than arboreal (tree-climbing) or aquatic species. Some are "sand swimmers", especially the desert species, such as the mole skink or sand skink in Florida. Some use a very similar action in moving through grass tussocks. Skinks that live largely covered by loose soil rely heavily on olfaction and touch. Breeding: Although most species of skinks are oviparous, laying eggs in clutches, some 45% of skink species are viviparous in one sense or another. Many species are ovoviviparous, the young developing lecithotrophically in eggs that hatch inside the mother's reproductive tract, and emerging as live births instead of eggs. Nesting: Skinks typically seek out sheltered environments out of the elements, such as thick foliage, underneath man-made structures, and ground-level buildings such as garages and first-floor apartments. When two or more skinks are seen in a small area, it is typical to find a nest nearby. Skinks are considered to be territorial and often are seen standing in front of or "guarding" their nest area. Blood color: Skinks in the genus Prasinohaema have green blood because of a buildup of the waste product biliverdin.

Ophisaurus- glass lizards

Appearance: resemble snakes, but are actually lizards. Although most species have no legs, their head shapes, movable eyelids, and external ear openings identify them as lizards. A few species have very small, stub-like legs near their rear vents.They reach lengths of up to 1.2 metres (4 ft), but about two-thirds of this is the tail. Diet: Glass lizards feed on insects, spiders, other small reptiles, and young rodents. Their diets are limited by their inability to unhinge their jaws. Reproduction: Some glass lizards give birth to live young but most lay eggs. Name/Autonomy: They are so-named because their tails are easily broken; like many lizards, they have the ability to deter predation by dropping off part of the tail, which can break into several pieces, like glass. The tail remains mobile, distracting the predator, while the lizard becomes motionless, allowing eventual escape. This serious loss of body mass requires a considerable effort to replace, and can take years to do so. Despite this ability, the new tail is usually smaller than the original. Distribution: Found all over the world. Several species live in the Southeastern United States, including the barrier islands off the Atlantic Coast of Florida. They are also found in abundant numbers in eastern North Carolina as far as 40 miles from the Atlantic Ocean

Anguidae- glass lizards and alligator lizard

Distribution: Native to the Northern Hemisphere Appearance: Anguids have hard osteoderms beneath their scales giving them an armored appearance. Many of the species have reduced or absent limbs, giving them a snake-like appearance, while others are fully limbed. Body type varies among species, with sizes ranging from 10 cm to 1.5 m. Reproduction: The group includes oviparous and viviparous species, both of which can be observed in a single genus at times. Diet: These lizards are known carnivores or insectivorous foragers, feeding primarily on insects, although larger species have been known to feed on small reptiles and amphibians. Habitat: They inhabit a wide range of different habitats across the globe, from arid to tropical environments. Most known species are terrestrial or semi-fossorial, with the exception of one arboreal genus, Abronia

Sceloporus- spiny lizards

Distribution: North America, mainly the U.S. Appearance: In external appearance, they are long-tailed, stocky lizards with a head of moderate size. All are capable of modest color changes. They are darkest when cold, inactive or beginning the day's basking, and lightest when optimum body temperature has been attained and the lizards are alert and foraging. The spiny lizards of the United States are clad dorsally in scales of rock gray or tree-bark brown, and they may be striped, marked with rearward directed chevrons, or both. They are of lighter coloration ventrally, and males of most have blue ventrolateral patches and a blue and black throat that is displayed to females and during territorial advertisements in a series of stylized pushups. Rather than blue, the aptly named rose-bellied lizard of Texas, Mexico and Central America, has rosy belly patches. Lifestyle: Insectivorous (eat insects). All spiny lizards are active heliotherms (basking lizards) that, in the wild, move quickly between sun-splashed boulders or into arboreal positions to avail themselves of optimum temperatures and prey availability. Although as a group these lizards are often referred to as arboreal, this term is not always accurate. Some, such as the eastern fence lizards, do climb trees, and the mesquite lizard is persistently arboreal. Others, like the large granite spiny lizard are rock dwellers (saxicolous) and are agile, wary and well-camouflaged Habitat: enjoy rock crevices and sunny areas Behaviour: Northern and high-elevation species brumate (the reptilian equivalent of hibernation) throughout the months of winter. Species in the deep south remain active throughout much of the year, remaining hidden and inactive during rainy, overcast weather or during the passage of cold frontal systems. Male vs Female: Males of most have blue belly and throat patches (rose on one species) of varying intensities and sizes. These flash colors are lacking or greatly reduced on most females. Additionally, males have a thickened tail base and enlarged femoral pores on the underside of each hind limb. All of these characteristics are most enhanced when the lizards are reproductively active.

Polychrida- Anoles

Distribution: United States and Mexico Unique Characteristics: have the ability to change color so often called 'American Chameleons'. While nearly all anoles can change their color, the extent and variations of this ability differ widely throughout the individual species. Underneath an anole's toes are pads that have several to a dozen flaps of skin going horizontally and covered in microscopic hairlike protrusions that allow them to cling to many different surfaces, much like a gecko. Have autotomy. Remarkably adaptable creatures. Appearance: Depends completely on species, pictures above and below (for anolis) reflect some of these species Habitat: Depends on species. When green anoles and brown anoles inhabit the same area, the brown anoles are primarily terrestrial or restrict themselves to the lower branches of bushes, while the green anoles stay higher. They usually inhabit regions around 3-6 m (9.8-.19.7 ft) high. Shrubs, walls, fences, bushes, and short trees are common hiding places Length: Many anoles are between eight and 18 cm (3-7 in) in length. Highest recorder length is 20 inches Diet: Anoles' diets include live insects and other invertebrates, with crickets, spiders, and moths being some of the most commonly consumed prey. Anoles are opportunistic feeders, and may attempt to eat any attractive meal that is small enough Reproduction: Breeding occurs for several months beginning in late spring. Males employ head bobbing and dewlap extension in courtship. One or two small, soft-shelled eggs are laid among leaf litter. More clutches may be laid before mating season has ended. How to tell between males and females: In green anoles, the female is characterized by a pale dorsal stripe extending from the neck to the tail, a generally smaller body, and a smaller head with a shorter snout. Female brown anoles share these characteristics, although their dorsal stripes are often wider, with diamond-shaped or squiggly edges. This stripe may be present sometimes in males, especially young ones not yet fully grown, but it is always fainter with less-defined edges. Some females have small dewlaps (pale and much smaller than those of the males). Territory/Territorial Behaviours: Anoles are very territorial. Their territories are usually quite small: around three square yards, with females' usually smaller. Their territories often contain a basking area, a shady area, a high lookout, and always a place to hide from predators. They do not tolerate other anoles in their territory. Often, when an intruder is in the area, the anole raises its spine, fans its dewlap, and does "push-ups" accompanied by intermittent ultrasonic hisses. If this does not scare off the intruder, a fight proceeds in which the two anoles bite at each other's tails. If the anole loses (gives up) the intruder gains entrance, otherwise he leaves. Females rarely fight.

Phrynosomatidae- earless, spiny, tree, side-blotched, and horned lizards

Distribution: found from Panama to the extreme south of Canada. (all of Mexico, most of USA, southern Canada) Habitat: Many members of the group are adapted to life in hot, sandy deserts, although the spiny lizards prefer rocky deserts or even relatively moist forest edges, and the short-horned lizard lives in prairie or sagebrush environments. Reproduction: The group includes both egg-laying and viviparous species, with the latter being more common in species living at high elevations Appearance: relatively small (most < 10 cm snout-vent length) lizards, and represent a diversity of forms. Have pleurodont teeth

Iguanidae- Iguanids Genus: Iguana

Distribution: native to tropical areas of Mexico, Central America, South America, and the Caribbean Unique Characteristics: possess a dewlap, a row of spines running down their backs to their tails, and a tiny "third eye" on their heads. This light-sensing organ is known as the parietal eye, visible as a pale scale on the top of the head, and cannot make out details, just brightness. Behind their necks are small scales which resemble spokes, known as tuberculate scales. These scales may be a variety of colors and are not always visible from close distances. They have a large round scale on their cheeks known as a subtympanic shield. Herbavours. Appearance: Iguanas are often hard to spot, as they tend to blend into their surroundings and their coloration enables them to hide from larger predators. Have taller and wider skulls, shorter snouts, and larger bodies relative to carnivorous and omnivorous reptiles. The teeth of the iguana are acrodontal, meaning that their teeth sit on top of the surface of the jaw bone and project upwards. The teeth themselves are small and serrated - designed to grasp and shear food Sight: Iguanas have keen vision and can see shapes, shadows, colors, and movement at long distances. Their visual acuity enables them to navigate through crowded forests and to locate food. They employ visual signals to communicate with other members of the same species. Size: range from 1.5 to 1.8 metres (5 to 6 ft) in length, including their tail

Cophosaurus and Holbrookia- earless lizards

Earless lizards are two genera of small lizards native to the semi-arid and grassland habitats of the southwestern United States and Mexico. Ears: The genus Cophosaurus (greater earless lizard) and the genus Holbrookia (lesser earless lizard) are both characterized by having no external ear openings, presumably to prevent sand from entering the body as they dig. Defense Mechanism: Earless lizards have a peculiar defense mechanism which is coupled to their cold-blooded lifestyle. They have a small opening on the top of their head called a 'blood sinus' which helps the lizard to gain heat quickly during daytime. However the blood can also be channelized to the eyes of the lizard when a predator looms close by, efficiently spitting the blood onto the predator giving it enough time to escape. Distribution: Earless lizards are found in Mexico and the southwestern and central United States Lifestyle: Holbrookia species are basking lizards. They spend the vast majority of their time sunning on rocks, even in the heat of the day, until the surface temperature reaches approximately 104°F, when they will retreat to a rock crevice or burrow. They are insectivorous. Appearance: Lesser earless lizards grow to approximately 2.0-2.5 inches (50-65 mm) snout-to-vent length, plus a tail 3-4 inches (75-100 mm) long. They are typically grey or tan in color, with black blotching. The males usually have blue patches on either side of their bellies, whereas the females do not. Females will often change to have bright orange patches when gravid.

Eumeces- skinks

HAS BLUE TAIL ONLY WHEN JUVENILE, FADES WITH AGE The genus Eumeces (family Scincidae) comprises four African to Middle-Eastern skink species. There are many more, but they have been moved to other genus.

Lacertidae- wall lizards

Habitat: The European and Mediterranean species live mainly in forest and scrub habitats. Eremias and Ophisops species replace these in the grassland and desert habitats of Asia. African species usually live in rocky, arid areas. Unique Characteristics: Holaspis is one of the few arboreal lacertids, and its single species, Holaspis guentheri, is a glider, using its broad tail and flattened body as an aerofoil. They are primarily insectivorous (carnivorous and eats insects). Well-developed limbs, pleurodont dentition, and deeply notched tongue Size: Lacertids are small or medium-sized lizards. Most species are less than 9 cm long, excluding the tail Appearance: Lacertids are remarkably similar in form, with slender bodies and long tails, but have highly varied patterns and colours, even within the same species. Their scales are large on the head, which often also has osteoderms, small and granular on the back, and rectangular on the underside. Most species are sexually dimorphic, with the males and females having different patterns. Distribution: all over the world

Iguana- green iguana

Lifestyle: The green iguana (Iguana iguana), also known as the American iguana, or just iguana, is a large, arboreal (lives in trees), mostly herbivorous species of lizard of the genus Iguana. Distribution: from southern Brazil and Paraguay as far north as Mexico and the Caribbean Islands. Size: It grows to 1.5 meters (4.9 ft) in length from head to tail, although a few specimens have grown more than 2 metres (6.6 ft) with body weights upward of 20 pounds (9.1 kg). Behaviour/Unique Abilities: Green iguanas are diurnal, arboreal, and are often found near water. Agile climbers, Iguana iguana can fall up to 50 feet (15 m) and land unhurt (iguanas use their hind leg claws to clasp leaves and branches to break a fall). During cold, wet weather, green iguanas prefer to stay on the ground for greater warmth. When swimming, an iguana remains submerged, letting its four legs hang limply against its side. They propel through the water with powerful tail strokes. Conservation: In South and Central America, where the green iguana is native, it is an endangered species in some countries because people have been hunting and eating this "chicken of the trees" for a long time Appearance: Despite their name, green iguanas can come in different colors. In southern countries of their range, such as Peru, green iguanas appear bluish in color with bold blue markings. On islands such as Bonaire, Curaçao, Aruba, and Grenada, a green iguana's color may range from green to lavender, black, and even pink. Green iguanas from the western region of Costa Rica are red and animals of the northern ranges, such as Mexico, appear orange. Most all species have yellow eyes. Green iguanas possess a row of spines along their backs and along their tails, which helps to protect them from predators. Their whip-like tails can be used to deliver painful strikes and like many other lizards, when grabbed by the tail, the iguana can allow it to break, so it can escape and eventually regenerate a new one. In addition, iguanas have a well developed dewlap, which helps regulate their body temperature. This dewlap is used in courtships and territorial displays. Have a parietal eye. SOme species have small horns on their nostrils. Sight: Green iguanas have excellent vision, enabling them to detect shapes and motions at long distances. As green iguanas have only a few rod cells, they have poor vision in low-light conditions. At the same time, they have cells called "double cone cells" that give them sharp color vision and enable them to see ultraviolet wavelengths. This ability is highly useful when basking so the animal can ensure that it absorbs enough sunlight in the forms of UVA and UVB to produce vitamin D. Teeth: Green iguanas have very sharp teeth that are capable of shredding leaves and even human skin.These teeth are shaped like a leaf, broad and flat, with serrations on the edge. The similarity of these teeth to those of one of the first dinosaurs discovered led to the dinosaur being named Iguanodon, meaning "iguana-tooth", and the incorrect assumption that it had resembled a gigantic iguana. The teeth are situated on the inner sides of the jawbones, which is why they are hard to see in smaller specimens. Osmoregulation: Primarily herbivorous, green iguanas are presented with a special problem for osmoregulation; plant matter contains more potassium and as it has less nutritional content per gram, more must be eaten to meet metabolic needs. As green iguanas are not capable of creating liquid urine more concentrated than their bodily fluids, like birds they excrete nitrogenous wastes as urate salts through a salt gland. As a result, green iguanas have developed a lateral nasal gland to supplement renal salt secretion by expelling excess potassium and sodium chloride. Dipsosaurus- desert iguana

Helodermatidae- Gila Monster

Lifestyle: carnivorous (eat meat) and oviparous (lay eggs) Distribution: native to the southwestern United States, Mexico, and as far south as Guatemala. Appearance: Helodermatids (or beaded lizards) are large, stocky, slow-moving reptiles. Their tails are short and used as fat storage organs. They are covered with small, nonoverlapping, bead-like scales, with osteoderms on the undersides of their bodies. Both species are dark in color, with yellowish or pinkish markings. Habitat: prefer semi-arid habitats Venom: Members of the family are venomous. Venom glands are located in their lower jaws, unlike snakes' venom glands, which are located in their upper jaws. Also, unlike snakes, helodermatids lack the musculature to inject venom. The venom is typically used only in defense, rather than in subduing prey, and the lizard must chew on its victim to work the venom into the flesh. Venom glands are believed to have evolved early in the lineage leading to the modern helodermatids, as their presence is indicated even in the 65-million-year-old fossil genus Paraderma. Venom production among lizards was long thought to be unique to this genus, but researchers studying venom production have proposed many others also produce some venom, all placed in the clade Toxicofera, which includes all snakes and 13 other families of lizards. However, except for snakes, helodermatids, and possibly varanids, envenomation is not considered medically significant for humans.

Uma- fringe toed lizards

Lifestyle: eat insects and plants Distribution: the deserts of North America Appearance/Anatomy: These lizards have a brown and tan coloration that helps them to blend in with the sand. The dorsal surface has a velvety texture with intricate markings. In addition, they also have prominent elongated scales which form a fringe on the sides of their hind toes. These fringes aid with traction and speed, and help the lizard avoid sinking into loose, sandy dunes. They also possess upper jaws which overlap the lower ones, preventing the intrusion of sand particles, and nostrils that can be closed at will. Flaps also close against the ear openings when moving through sand, and the upper and lower eyelids have interlocking scales that prevent sand from getting into the eyes Habitat: They are found in low desert areas having fine, loose sand.

Teiidae- whiptails

Lifestyle: terrestrial (some are semi-aquatic). Primarily carnivorous or insectivorous Distribution: Native to the Americas Unique Characteristics/ Appearance: The Teiidae includes several parthenogenic species - a mode of asexual reproduction. They have large rectangular scales that form distinct transverse rows ventrally (lower side/underbelly) and generally small granular scales dorsally (upper side/ on its back). They have head scales that are separate from the skull bones, and the teiid teeth are solid at the base and "glued" to the jaw bones. Have a forked, snake-like tongue. The tongue is forked and used mainly or exclusively to sense the environment, continually flicking out to sample the environment, and back to transfer molecules to the vomeronasal organ responsible for chemosensation, analogous to but different from smell or taste. They all possess well-developed limbs. Behaviour: Most teiids forage quite actively within their ideal temperature range, quickly skirting between cover objects. Some will include a small amount of plant matter in their diet. They are oviparous, and some species laying very large clutches Reproduction/Pseudocopulation: Several species of whiptail lizards are entirely female. These all-female species reproduce by obligate parthenogenesis. Like all squamate obligate parthenogenetic lineages, parthenogenetic Teiids are hybrids. Two or more species rarely hybridize and the offspring are thought to occasionally be capable of reproduction without sperm. Primarily known from lab studies of parthenogenetic Aspidoscelis neomexicanus (New Mexican Whiptail), simulated mating behavior can increase fertility. In this behavior known as pseudocopulation, one female assumes a male-like role and the other a female-like role. Individuals can switch roles throughout their life. The behavior has not been observed in all parthenogenetic varieties. Since at least some all-female lineages exhibit pseudocopulation, these lizards can be considered to reproduce unisexually (in contrast to asexually).

Dipsosaurus- desert iguana

Lifestyle: terrestrial, dig burrows. Primarily herbivores Distribution: the Sonoran and Mojave deserts of the southwestern United States and northwestern Mexico. They also occur on several Gulf of California islands Appearance: The desert iguana is a blunt, medium-sized lizard which grows to 61 cm (24 in) including the tail. They are pale gray-tan to cream in color with a light brown reticulated pattern on their backs and sides. Down the center of the back is a row of slightly-enlarged, keeled dorsal scales that become slightly larger as you move down the back. The reticulated pattern gives way to brown spots near the back legs, turning into stripes along the tail. The tail is usually around 1½ times longer than the body from snout to vent. The belly is pale. During the breeding season, the sides become pinkish in both sexes. Habitat: Their preferred habitat is largely contained within the range of the creosote bush, mainly dry, sandy desert scrubland below 1,000 m (3,300 ft). It can also be found in rocky streambeds up to 1,000 m. In the southern portion of its range this lizard lives in areas of arid subtropical scrub and tropical deciduous forest. These lizards can withstand high temperatures and are out and about after other lizards have retreated into their burrows. They burrow extensively and if threatened will scamper into a shrub and go quickly down a burrow. Their burrows are usually dug in the sand under bushes like the creosote. They also often use burrows of kit foxes and desert tortoises. Reproduction: Mating takes place in the early spring. It is believed that only one clutch of eggs is laid each year, with each clutch having 3-8 eggs. The hatchlings emerge around September

Phrynosoma- horned lizards

Name: The common name is a metaphor prompted by the horntoad's flattened, rounded body and blunt snout, which make the common name "horntoad" natural and easy to remember. The taxon Phrynosoma means "toad-bodied". Behaviour: In common with larger true frogs and toads, horntoads tend to move sluggishly, making them easy to hand-catch; this may also avoid triggering attacks by predators. They are adapted to desert areas. Anatomy: The spines on the lizard's back and sides are made from modified reptile scales which prevent the water loss through the skin, whereas the horns on the head are true horns (i.e. they have a bony core). Their coloration generally serves as camouflage. Defense Mechanisms: When threatened, their first defense is to remain still to avoid detection. If approached too closely, they generally run in short bursts and stop abruptly to confuse the predator's visual acuity. If this fails, they puff up their bodies to cause them to appear more horned and larger, so that they are more difficult to swallow. To avoid being picked up by the head or neck, a horned lizard ducks or elevates its head and orients its cranial horns straight up, or back. If a predator tries to take it by the body, the lizard drives that side of its body down into the ground so the predator cannot easily get its lower jaw underneath. Blood squirting: At least eight species are also able to squirt an aimed stream of blood from the corners of the eyes for a distance of up to 5 feet (1.5 m). They do this by restricting the blood flow leaving the head, thereby increasing blood pressure and rupturing tiny vessels around the eyelids. This not only confuses predators, but also the blood tastes foul to canine and feline predators. It appears to have no effect against predatory birds. Only three closely related species are certainly known to be unable to squirt blood. Conservation: horned lizard populations continue to disappear throughout the southwest despite protective legislation. Population declines are attributed to loss of habitat, human eradication of the ant populations upon which the lizards prey, displacement of native ant populations by invading fire ants (aided by synergistic effects of native ant eradication), and predation by domestic dogs and cats

Cnemidophorus- racerunners and whiptails

Name: The name Cnemidophorus literally means "greave-wearing". A greave is a piece of armor used to protect the shin. Appearance: long, slender lizards with pointed snouts and extremely long tails. Snout-vent lengths range from 2¾ inches (69 mm) to 5¼ inches (137 mm) among the various species of whiptails. Habitat: These lizards occupy low desert scrub through grasslands, woodlands and pine forests. They are often found under rocks or nosing around leaf litter. Reproduction: Most species reproduce sexually and lay 1 or more clutches of 1 to 6 eggs in late spring or early summer. However, in Arizona approximately 60 percent of whiptail species are parthenogenetic, meaning that they reproduce asexually. These species, such as the Sonoran spotted whiptail (C. sonorae), consist entirely of genetically identical females that lay unfertilized eggs, creating a population of clones. Oddly enough, many of the behaviors exhibited by sexually reproducing species are expressed by these parthenogenetic lizards. Females will engage in pseudocopulation and mount and bite other females. Apparently this triggers hormonal changes necessary for ovulation and egg laying. Eggs typically take 60 to 75 days to hatch regardless of reproductive style.

Gerrhonotus- alligator lizard

Name: gets its name from its vague resemblance to an alligator Distribution: America and Mexico Appearance: a medium-sized lizard, attaining a length (including tail) around 24 to 25 in (61 to 64 cm), generally smaller. These lizards have flat, wedge-shaped heads. They are generally a yellow-brown color, often with darker brown and white checker patterning on their dorsal surfaces, and uniformly light-colored, white, or grey on their ventral surfaces. Their scales are very stiff and plate-like. They have short limbs, and a tail that can fall off to distract a potential predator, but will regrow in time. Habitat: They are often found on rocky hillsides, where they hide among the stones or in limestone crevices. Diet: Their primary diet is insects and other invertebrates, but they may sometimes prey on nestling birds or rodents. Reproduction: Breeding occurs year-round; sometimes, multiple clutches of eggs are laid per year. Females will often stay near the nesting site to protect it, but no parental care occurs once the young alligator lizards hatch. The young generally have more striking markings

Crotaphytidae- collared lizards

Size: 8-15 in (20-38 cm) in length (including the tail) Distribution: Chiefly found in dry, open regions of Mexico and the south-central United States. State reptile of Oklahoma. Appearance: large head and powerful jaws. Has bands of black around neck. Males have a blue-green body with a light brown head. Females have a light brown head and body. Small body scales and long, strong hind limbs. Territorialism: In captivity if two males are placed in the same cage they will fight to the death Unique Characteristics: They are well known for the ability to run on their hind legs, looking like small versions of the popular images of theropod dinosaurs. The name "collared lizard" comes from the lizard's distinct coloration, which includes bands of black around the neck and shoulders that look like a collar. Relatively fast sprinters

Sauromalus- chuckwalla

The six species of chuckwallas are all placed within the genus Sauromalus; they are part of the iguanid family, Iguanidae. Lifestyle: herbivores. Ectothermic, spend much of their mornings and winter days basking. These lizards are well adapted to desert conditions; they are active at temperatures up to 102°F (39°C). Juveniles emerge first, then adults, as temperatures reach around 90°F. Chuckwallas hibernate during colder months and emerge in February Distribution: arid regions of the southwestern United States and northern Mexico. Some are found on coastal islands. Name: The generic name, Sauromalus, is a combination of two Ancient Greek words:σαῦρος (sauros) meaning "lizard" and ομαλυς (omalus) meaning "flat". Appearance: Chuckwallas are stocky, wide-bodied lizards with flattened midsections and prominent bellies. Their tails are thick, tapering to a blunt tip. Loose folds of skin characterize the neck and sides of their bodies, which are covered in small, coarsely granular scales. The common chuckwalla (Sauromalus ater) measures 15 3/4 inches long, whereas insular species such as the San Esteban chuckwalla of San Esteban Island (Sauromalus varius) can measure as long as 30 in. Males vs Females: They are sexually dimorphic, with males having reddish-pink to orange, yellow, or light gray bodies and black heads, shoulders, and limbs; females and juveniles have bodies with scattered spots or contrasting bands of light and dark in shades of gray or yellow. Males are generally larger than females and possess well-developed femoral pores located on the inner sides of their thighs; these pores produce secretions believed to play a role in marking territory Habitat: Chuckwallas prefer lava flows and rocky areas typically vegetated by creosote bush and other such drought-tolerant scrub. The lizards may be found at elevations up to 4,500 ft (1,370 m). Reproduction: Mating occurs from April to July, with five to 16 eggs laid between June and August. The eggs hatch in late September. Chuckwallas may live for 25 years or more. Territorialism: Males are seasonally and conditionally territorial; an abundance of resources tends to create a hierarchy based on size, with one large male dominating the area's smaller males. Chuckwallas use a combination of color and physical displays, namely "push-ups", head-hobbing, and gaping of the mouth, to communicate and defend their territory.

Urosaurus and Uta- tree and side blotched lizards

Tree Lizard (Urosaurus) Distribution: native to the southwestern United States and northwestern Mexico Diet: Feeds mostly on insects Reproduction: A group consisting of one male and one or more females typically inhabit an area containing one or more large trees, shrubs, or boulders. The male copulates with each female and the female retain eggs about two weeks after mating. In many parts of its range, females may lay more than one clutch of eggs a year. Territorialism: Territoriality is an important part of reproduction for many males in this species. Males often defend territories by aggressively excluding other males. This aggression can, in part, be enhanced with higher levels of the steroid hormones testosterone and progesterone. Females have home ranges but do not defend territories. When the number of females on a male's territory is experimentally reduced by removing the females, the male is more likely to abandon his territory. Throat Color: Females also can vary in throat coloration, although this is not as well-studied. When gravid with eggs, females tend to be orange or red. Recent experiments also suggest females have association, and perhaps mating preferences for different male types, and that this female preference varies with the throat color of the female herself, and with the colors of the two males that she was presented. Side Blotched Lizard (Uta) Distribution: U.S. and Mexico Appearance: Uta species range in length from 10 to 27 cm (4 to 11 inches). They are usually dull-coloured; the males of some species have a blue throat and abdomen. The degree of pigmentation varies with sex and population. Some males can have blue flecks spread over their backs and tails, and their sides may be yellow or orange, while others may be unpatterned. Females may have stripes along their backs/sides, or again may be relatively drab. Both sexes have a prominent blotch on their sides, just behind their front limbs. Coloration is especially important in common side-blotched lizards, as it is closely related to the mating behavior of both males and females. Behaviour: These lizards are climbers and are commonly found on bushes and large rocks. Uta seldom move far from protective cover, prey mainly on insects, and are egg layers. Mating: this species is known for their unique mating pattern. The ways a lizard mates depends on the color of their throat, ending up with three groups: Orange Throated Males, Yellow Throated Males, and Blue Throated Males. They work in a rock-paper-scissors mechanism, as in each of them can conquer another but be beaten by the third. Females also work in colorintion; Orange Throated Females usually produce large crutches with smaller eggs, while Yellow Throated Females lay fewer, but larger, eggs