Oklahoma is rich in reptiles and amphibians, ranking third of all fifty states in number of species. Eighty species are represented, including one alligator, seventeen turtle, eighteen lizard, and forty-six snake species; and fifty-one species of amphibians are also present, including twenty-three salamander and twenty-eight frog and toad species. The state reptile is the collared lizard (Crotaphytus collaris, also called mountain boomer, although it is mute).This large lizard, which can run on its hind legs, reaches a total length of fourteen inches and is found on sunny, rocky outcrops statewide. The American alligator (Alligator mississippiensis) is rare in Oklahoma, found only in the extreme southeastern corner of the state. It is the only Oklahoma reptile with current state and federal conservation protection.
Of the turtles, one of the most interesting is the alligator snapping turtle (Macrochelys temminckii). This is the largest freshwater turtle in North America, with males reaching 250 pounds or more. Found in the eastern part of Oklahoma, it is rarely seen because it spends its entire life at the bottom of slow-moving rivers and creeks, except for females, who briefly leave the water to lay eggs. This turtle has a pink, fleshy protuberance in its mouth, which it wriggles while its mouth is held open. Curious fish approach this "worm" mimic and are captured by the turtle's jaws, strong enough to break a man's arm. The common snapping turtle (Chelydra serpentina), is also quite large, commonly reaching thirty-five pounds. Oklahoma's other turtles are much smaller and mostly aquatic, except for two species of terrestrial box turtles (Terrapene carolina and Terrapene ornata).
Noteworthy Oklahoma lizards (other than the state reptile mentioned above) include the Texas horned lizard (Phrynosoma cornutum), or horny toad, which is not a toad at all. This species has declined drastically in the last fifty to eighty years. It is a flattened, pancake sort of lizard, with sharp spines along its sides and stout horns projecting from the back of its head. It eats mostly ants and relies on its cryptic coloration to blend into its surroundings to escape predation. If severely disturbed by a dog or coyote, though, the horny toad is capable of spurting blood from the suborbital sinuses of its eyes, blood that apparently contains a substance that drives off the would-be predator. In southeastern Oklahoma lives the green anole (Anolis carolinensis), the popular "chameleon" sold in pet stores. This delicate lizard is arboreal and, like the true Old World chameleons (but not to the same extent), can change color from a drab brown to a bright emerald green.
Other lizards are long-tailed, actively foraging racerunners or whiptails (Teiidae), and smooth-scaled, shiny skinks (Scincidae). The slender glass lizard (Ophisaurus attenuatus) has no legs and is more tail than body. It is a lizard, though, as it has moveable eyelids and external ear openings. The Mediterranean house gecko (Hemidactylus turcicus) has been introduced from Texas (where it was introduced from the Mediterranean) to buildings on the campus of the University of Oklahoma and perhaps elsewhere in the southern part of the state. It is nocturnal, and the undersides of its toes have special microscopic, hairlike structures that allow it to climb on walls. It is the only species of lizard in Oklahoma that vocalizes. This, and some of the other lizards of Oklahoma (especially the skinks), can actively shed its tail (autotomy) if a predator grabs it, so as to be able to escape with its life. The tail can then regenerate.
Oklahoma sports more species of snakes than any other kind of reptile. There are blind snakes, hog-nosed snakes, wormsnakes, flat-headed snakes, groundsnakes, rough greensnakes, coachwhips, racers, ratsnakes, kingsnakes, milksnakes, bullsnakes, brownsnakes, earthsnakes, lined snakes, ribbonsnakes, gartersnakes, crayfish snakes, and watersnakes, among others. Probably the most common snake in Oklahoma is the small, gray ring-necked snake (Diadophis punctatus), usually found under rocks and logs. Although it is harmless to humans, this species can exude from its mouth a noxious fluid. When confronted by a potential predator, the snake will tightly coil its tail and flash its underside, which has a series of bright red and black bands, to warn or startle the molester.
Oklahoma has seven species of truly venomous snakes: the copperhead (Agkistrodon contortrix), cottonmouth or water moccasin (A. piscivorous), and five species of rattlesnakes, the Massasauga (Sistrurus catenatus), western pigmy (S. miliarius), timber (Crotalus horridus), western diamondback (C. atrox), and prairie rattler (C. viridis). All of these species are pit vipers, that is, between the eye and the nostril they have a heat-sensitive gland that is used to detect warm prey. The timber and diamondback rattlesnakes can grow especially large, over six feet long. Their rattles emit a loud, menacing warning sound, whereas the rattle of the much smaller Massasauga and western pygmy rattlesnake is nearly inaudible.
Turning to the amphibians, most of the salamanders require moist habitats and are found only in the eastern part of the state. They range in size from the diminutive, two-inch to three-inch Oklahoma salamander (Eurycea tynerensis), which reproduces in its gilled larval form, to the eighteen- to thirty-inch, three-toed amphiuma (Amphiuma tridactylium), which is aquatic and has extremely tiny limbs that cannot support its weight. One species, the central newt (Notophthalmus viridescens), has a complex life cycle in which it hatches from aquatic eggs into gilled larvae that live in small, fishless ponds. These larvae metamorphose into lunged efts, living on land for a few years, eventually returning to their natal ponds to take up an aquatic life again as gill-less newts. Here they reproduce. This species has highly toxic skin secretions and, especially the eft form, is bright red to warn potential predators. Most salamanders lay aquatic larvae that hatch into gilled larvae, but one genus (Plethodon) lays terrestrial eggs, in moist forest litter, moss, under logs, and so forth, that hatch into miniature, terrestrial adults. Interestingly, these adults lack both gills and lungs, "breathing" through their skin.
Of the frogs and toads, the most common and widespread species is the tiny cricket frog (Acris crepitans), which is often found along the shoreline of lakes and ponds. Unlike salamanders, frogs and toads vocalize; males sing to attract females for breeding. The call of the cricket frog sounds like two marbles repeatedly struck together. In contrast, the call of the also-abundant American toad (Bufo americanus) is a high-pitched trill lasting six to thirty seconds. This species, and its relatives, has a rough, warty skin containing irritating toxins that repel potential predators. On the back, just behind the head, are a pair of prominent parotid glands that deliver copious amounts of this chemical. Other frogs and toads of Oklahoma include treefrogs, with suction-cup toe tips to help them climb; narrowmouth toads, which often live together with tarantulas in their burrows; spadefoot toads, which live in more arid parts of the state and breed only after heavy summer rains; and true frogs, which include the largest frog of the state, the bullfrog (Rana catesbeiana). All of the state's species lay aquatic eggs that hatch into aquatic larvae (tadpoles) that later metamorphose into adults.
BIBLIOGRAPHY: Jeffrey H. Black and Gregory Sievert, A Field Guide to Amphibians of Oklahoma (Oklahoma City, Okla.: Oklahoma Department of Wildlife Conservation, 1989). Charles C. Carpenter and James J. Krupa, Oklahoma Herpetology: An Annotated Bibliography (Norman: University of Oklahoma Press, 1989). Roger Conant and Joseph T. Collins, Reptiles and Amphibians of Eastern/Central North America, Peterson Field Guide Series (3rd ed.; Boston: Houghton Mifflin, 1998). F. Harvey Pough, et al., Herpetology (2nd ed.; Upper Saddle River, N. J.: Prentice-Hall, 2001). George R. Zug, Laurie J. Vitt, and Janalee P. Caldwell, Herpetology: An Introductory Biology of Amphibians and Reptiles (2nd ed.; San Diego, Calif.: Academic Press, 2001).
Stanley F. Fox
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