Amphibians

 

Red-spotted toad at Amistad National Recreation Area

NPS Photo

Though the hot, dry climate of the Trans-Pecos region may not seem the ideal environment for amphibians, nine species have been identified within the park’s boundaries. Among these are the Couch’s spadefoot toad (Scaphiopus couchii), Rio Grande leopard frog (Rana berlandieri), and the Great Plains narrow-mouthed toad (Gastrophryne olivacea).

Because amphibians lack the ability to generate body heat, they must rely on the environment to regulate their body temperature. During the day, many amphibians will attempt to escape the heat by hiding in rock crevices and under plants or by burrowing into the soil. The Great Plains narrow-mouthed toad has even been known to use rodent and tarantula burrows to escape the heat.

Frogs and toads are the most commonly found amphibians within the park. Though very similar in appearance, frogs generally have smooth skin and long legs, while toads are characterized by bumpy skin and short legs that they use to hop or walk. Toads are a little better acclimated to drier environs, while frogs generally prefer moister areas.

Because they are primarily nocturnal, amphibians can be difficult to spot and are most easily seen at twilight or at night with the help of a flashlight. Each species has a distinctive call, or voice, that can be used to identify it from other species. Fpr example, the guttural trill of the Rio Grande leopard frog is easily distinguishable from the bird-like call of the Red-spotted toad (Anaxyrus punctatus).

Remember, all amphibians are protected against being harassed, killed, or collected within park boundaries. Like other animals in the park, visitors are not permitted to handle or disturb amphibians in any way.

 

Blanchard's Cricket Frog

NPS Photo

Blanchard’s Cricket Frog

Acris blanchardi

The Blanchard's cricket frog can be seen in sunny areas with a permanent water source. Observation is difficult due the frog’s alert and agile nature. When threatened, this frog jumps rapidly and erratically. Another factor that makes observation difficult is the frogs small size of 1 to 1 ½ inches. Like most other toads and frogs, the females of this species are larger and more robust.

 

Couch's Spadefoot Toad

NPS / J. Borgmeyer

Couch’s Spadefoot Toad

Scaphiopus couchii

The spade on this toad is elongate and sickle-shaped, and the eyelid diameter is equal to the distance between the eyes. They prefer short-grass plains, mesquite savannahs, and other arid regions. The name originates from Darius Nash Couch, an Army soldier in 1853 who was known for collecting natural history specimens while on leave in northeastern Mexico.

 

• Couch's Spadefoot Toad

  
  

  This sound was recorded at Saguaro National Park in Arizona.

  Credit / Author:

  NPS

  Audio Transcript

  The squelching ribbiting sound of Couch's Spadefoot Toads with background sounds of crickets chirping at night.

 

Eastern Green Toad with vocal sac billowed out

NPS Photo

Eastern Green Toad

Anaxyrus debilis

This toad has a shrill call, similar to a policeman’s whistle, lasting for 5-6 seconds per interval. March to September is the breeding season but only if it rains during that time frame. They are easy to identify by their flattened body and head, bright green color, and numerous warts that differ in color between male and female.

 

Great Plains Narrow-mouthed Toad

NPS Photo

Great Plains Narrow-mouthed Toad

Gastrophryne olivacea

An oddly-shaped body and a near lack of pattern make this toad fairly easy to identify. They can be found hiding anywhere that is slightly damp, even rodent burrows. Some even have been found in tarantula burrows and seem to derive some protection from the spider. Their secretion can cause a distasteful or burning sensation in the mouth and eyes and is thought to protect them from their main prey... ants!

 

Red-spotted Toad

NPS Photo

Red-spotted Toad

Anaxyrus punctatus

A small toad, as compared to others in this area, the red-spotted toad has a flattened body, painted snout, and large, widely spaced eyes. Their color can range from light gray to olive and reddish-brown usually with small, reddish warts. Specimens noted around the Edwards Plateau limestone are pale gray and virtually unmarked. The red-spotted toad is most active at twilight, and its high-pitched call, which is sometimes confused with that of a cricket, can be heard emanating from the rock along the shoreline.

 

Rio Grande Leopard Frog

NPS Photo

Rio Grande Leopard Frog

Lithobates berlandieri

The pale green to tan coloring of the Rio Grande leopard frog is less vibrant than other leopard frog species, and the light line along its upper jaw is less defined. Though adapted to arid conditions, this frog prefers to be near water and will burrow under rocks to escape the heat. The Rio Grande leopard frog can be identified by its rapid, guttural trill. This frog is noted for eating a wide variety of insects and almost anything else smaller than itself.

 

Texas Toad

NPS Photo

Texas Toad

Anaxyrus Speciosus

The Texas toad is often spotted at night and in rainy weather. Like most other frogs and toads, the Texas toad will burrow into moist sandy soil in order to escape the sun and heat during the day. Coloration of the Texas toad varies from olive-brown to olive-grey. It is distinguishable from other varieties of toads by the lack of defined patterns on its back.