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Amphibian and Reptile Checklists of the United States

Rocky Mountain Arsenal National Wildlife Refuge

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Commerce City, Colorado


The Rocky Mountain Arsenal National Wildlife Refuge offers a unique opportunity for wildlife watchers. Located only 10 miles northeast of Denver, Colorado, this 27-square-mile site provides wetland, grassland, and open water habitats for a variety of reptile and amphibian species. These animals are often difficult to spot in the wild, adding to their intrigue and mystery.


Amphibians are totally dependent on water during their early stages of development. They must remain in moist habitats because they constantly lose water through their skin. Females lay their eggs directly in water or moist places where the larvae hatch and grow independently. The two most common groups of amphibians are those that have tails (salamanders, newts, and mudpuppies) and those that do not (frogs and toads).

Amphibians, like most animals, have some type of defense against potential predators. A Woodhouse's toad will "puff up" when caught, making it hard for predators to swallow. Camouflage is also used as a means of protection; often times amphibians are heard but not seen. The croak of the striped chorus frog sounds like a fingernail being run across the blade of a comb; the northern leopard frog sounds like a motorboat; and the bullfrog calls out with a deep "jug-a-rum, jug-a-rum."


Reptiles have dry scaly skin that slows water loss. Therefore, they can live away from open water. Reptile eggs, like bird eggs, have protective outer coverings that prevent the embryos from drying out and enables them to develop outside of water. Reptiles cannot regulate their body temperature internally the way mammals can. They rely on their environment and behavior for warmth. (Scientists think some amphibians also do this.) Have you ever seen a lizard do "push-ups?" It is actually increasing its body temperature through a behavior called stilting!

A colorful snake to look for on the Refuge is the eastern yellow-bellied racer. It moves quickly, so keep your eyes open! This reptile preys on rattlesnakes, the only venomous snake on the Refuge, and is immune to their venom. Large bullsnakes often are seen basking in the sun along the Refuge's roadways. Bullsnakes resemble rattlesnakes and may shake their tails to discourage potential predators.

While visiting the Refuge, you can help protect the land and wildlife found here by practicing and promoting ethical wildlife viewing. Please do not disturb or attempt to handle wildlife. In addition, please do not litter or feed wildlife.

This list provides the common and scientific names as well as a brief description of the 18 different reptiles and amphibians sighted at the Refuge.

The code system reflects the relative abundance of each reptile or amphibian at the Refuge. The likelihood that you will observe a reptile or amphibian in its habitat may be inferred from the code it receives. Many reptiles and amphibians utilize more than one habitat and are indicated as such on the list.

HABITATS:                                  ABUNDANCE:

W - Wetlands                               C - Common
O - Open Water                             U - Uncommon
G - Grasslands                             R - Rare

AMPHIBIANS W O G SALAMANDERS Tiger salamander c c u (Ambystoma trigrinum) Slimy skin; yellowish bars or spots on dark colored back. It preys on snails, bugs, beetles, and larvae. Its predators include bullfrogs, turtles, ducks, and coyotes. TOADS Plains spadefoot toad u r c (Scaphiopus bombifrons) Single, black, wedge-shaped "spade" on each hind foot; vertical pupils. The plains spadefoot toad enters water only to mate. This toad displays the unique characteristic of twisting its hind feet in the sand as if it were snuffing out a lit match. This behavior aids the toad in burying itself. It preys mainly on moths, beetles and other insects. Two of its main predators are rattlesnakes and Swainson's hawks. Woodhouse's toad c c u (Bufo woodhousii) Rough and warty skin: light colored stripe runs along the middle of the back. This toad breeds in still water. It preys on scorpions, beetles, and grasshoppers. The garter snake is its main predator. FROGS Striped chorus frog c c r (Pseudacris triseriata) Green or brown stripe runs through eye from nose to groin. The striped chorus frog can be heard singing in the spring. It preys on flies, bugs, beetles, and ants. Robins, garter snakes, and smallmouth bass are some of its common predators. Bullfrog c c r (Rana catesbeiana) Plain green backside fully-webbed hind toes. When startled, this frog usually squawks and leaps into the water. Bullfrogs are eliminating native leopard frogs from some areas of Colorado because of competition and predation. It preys on any animal that can be captured and swallowed. Northern leopard frog u u r (Rana pipiens) Large dark spots on back: light line on upper jaw. It preys on a wide variety of insects. Bullfrogs, garter snakes, and tiger salamanders are its main predators.
REPTILES W O G TURTLES Common snapping turtle u u r (Chelydra serpentina serpentina) Brown to black shell; rear edge is saw-toothed; strong jaws and an unpleasant disposition. This turtle is not very particular about its diet. It eats anything it can capture including non-living materials. This turtle has no predators on the Refuge. However, off the Refuge, people are the main predators because of the turtle's tasty flesh. Western painted turtle u u r (Chrysemys picta bellii) Yellow streaks on head, neck, and legs are contrasted against a dark body and shell. This turtle sleeps partially submerged in water at night and then basks in the sun before feeding. It feeds on a variety of living and dead plants and animals. Spiny softshell u u r (Trionyx spiniferus) Soft, flexible shell; long tubular snout. Sunny banks of rivers, streams, or ponds are the favored resting spot for these distinctive turtles. Crayfish and insects~are its preferred foods. LIZARDS Lesser earless lizard r r c (Holbrookia maculata) No visible ear openings; female's skin is tinted with orange during and shortly after breeding season, otherwise resembles color of habitat. This unique lizard is active during the day. It preys on bugs, ants, and beetles. At the Refuge, this lizard is the favorite food of young kestrels. SKINKS Many-lined skink r r c (Eumeces multivirgatus) Long, slender body. This feature allows it to take refuge under rocks, logs, and trash. It is a challenge to spot because it is a fast mover. This reptile preys on a variety of insects. The kestrel is an occasional predator. SNAKES Western hognose snake u r u (Heterodon nasicus) Prominent shovel-like snout; belly has extensive black areas. The prominent rear teeth of this snake are used to puncture and deflate toads. This snake will occasionally fake its death to repulse predators. It preys on toads and lizards which it finds by its keen sense of smell. Eastern yellow-bellied racer c u u (Coluber constrictor flaviventris) Plain olive skin on upper body; cream or yellow belly. This snake is not a constrictor as its scientific name implies. It preys on small mammals, birds, reptiles, amphibians, and large insects. This racer also preys upon newborn western rattlesnakes to whose venom it is immune. Western bullsnake c r c (Pituophis melanoleucus sayi) Yellowish upper body; numerous dark-colored blotches on upper body. As a defense mechanism, a bullsnake will shake its tail to imitate a rattlesnake. It preys mostly on rodents making it very beneficial to farmers, ranchers, and residents of suburban areas. Western terrestrial garter snake c u u (Thamnophis elegans) Pale stripes along both sides of the body; center stripe fades at mid-body. This non-venomous snake emits a foul smell when first captured by a predator. Many garter snakes exhibit this defense. It preys on fish, salamanders, frogs, toads, and small rodents. Plains garter snake c u u (Thamnophis radix) Bold yellow or orange stripe along middle of back. It preys on earthworms, grasshoppers, and several types of frogs. Common garter snake c u u (Thamnophis sirtalis) Red blotches between pale stripes along the back. This snake is most active on sunny days. It preys on frogs and other amphibians. Prairie rattlesnake u r c (Crotalus viridis viridis) Wide head with narrow neck; diamond shapes on back of brown body; rattle on the end of the tail. It is non-aggressive; if left alone it will retreat to a hiding place. If cornered or harassed, it may coil and/or strike. It preys on a variety of lizards and rodents. Racers and golden eagles are occasional predators.

For additional information contact:
                       Rocky Mountain Arsenal NWR
                       Building 613
                       Commerce City, Colorado 80022           
                       Telephone: 303/289-0232
This resource is based on the following source:
U.S. Fish and Wildlife Service.  1994.  Amphibians and Reptiles of Rocky 
     Mountain Arsenal National Wildlife Refuge.  U.S. Fish and Wildlife 
     Service.  Unpaginated.
This resource should be cited as:
U.S. Fish and Wildlife Service.  1994.  Amphibians and Reptiles of Rocky 
     Mountain Arsenal National Wildlife Refuge.  U.S. Fish and Wildlife 
     Service.  Unpaginated.  Jamestown, ND: Northern Prairie Wildlife 
     Research Center Online.
     (Version 22MAY98).

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