Occasionally people ask me to identify creatures they describe on the phone. The caller attempts to relay distinguishing features while I try to piece together the image of what they are describing. How big and what color is it? Where was it? What was it doing? These are the questions that usually help to ferret out the mystery animal's identity. Occasionally, I get asked to identify a creature by sound, a much more difficult task to say the least. Such was the case a few days ago.

"It was very loud and it kept me awake most of the night," the caller said. "There were lots of them making noise all night long."

"Can you describe what they sounded like?" I asked.

"They were loud and sounded like someone yelling. There were some others that sounded like grunting or perhaps snoring," the caller replied.

After a few more questions and several poor imitations of animal sounds on my part, we deduced the sleepless night had been the result of a chorus of two species of amphibians, one of which was the plains spadefoot toad (Spea bombifrons). With the recent rains and warm temperatures, many species of frogs and toads have been making the most of the favorable breeding conditions.

The plains spadefoot toad is the most easily recognized toad in Montana because they have a distinctive vertical pupil like that of a cat. All other toads and frogs in the state have horizontal pupils. Spadefoot toads vary from a light cream, to gray or brown in color. Plains spadefoot toads resemble other toads in shape and size but have smoother, thinner skin similar to a frog's skin.

Spadefoot toads are found in the more arid regions of western North America. They occupy habitats ranging from deserts in the Southwest to aspen parklands in the Canadian prairies and are well adapted to these dry conditions.

Spadefoot toads are named for a large, sharp spur or spade on their back feet. These large, black tubercles are used to burrow backwards into the soil to conserve moisture. Summer burrows are generally shallow but are deep enough to avoid drying out. Winter burrows have been documented to nearly 15 feet deep. Spadefoot toads cannot survive freezing temperatures and must burrow below the frost. Most winter burrows are only a few feet deep. Spadefoots will occasionally use rodent burrows to overwinter. They emerge in the spring with spring rains when the temperature reaches around 50 degrees.

The breeding season of the plains spadefoot is not well defined, generally early May through June in Montana. However, if suitable conditions do not occur during the active season, they may not breed at all and may go several years without reproducing.

During periods of heavy rains and warm temperatures, large numbers of spadefoot toads will emerge and quickly migrate to breeding ponds. During amplexus -- the clasping posture of fertilization -- the eggs are deposited on the bottom or attached to partly submerged vegetation or other objects. Females can lay more than 2,000 eggs in masses of up to 250 eggs. The eggs hatch in about two days and the tadpoles metamorphose into toadlets in about two weeks depending on temperature and other environmental factors.

Spadefoot tadpoles often occur in two morphs in the same pond. The omnivorous morphs feed on suspended matter, organic debris, algae, plant tissue, and plankton. The larger, carnivorous morphs have much larger jaw muscles and stronger mouth parts. They eat relatively large aquatic invertebrates, insect larvae, fairy shrimp as well as other amphibian larvae, including cannibalizing their own species.

Spadefoot toads generally do not remain underground for years at a time during periods of extended drought. Rather, during periods of humid weather following a rain, they will emerge from their burrows at dusk and feed on beetles, crickets, grasshoppers, ants, spiders, moths, caterpillars and other small arthropods during the night. Occasionally, sticky matter secreted from their skin is seen at the entrance. It is thought this may help to prevent burrow collapse. As the daylight approaches bringing dryer conditions, spadefoot toads retreat to their burrows.

As the summer continues and the soil becomes drier, spadefoots burrow deeper to find moist soil. As the soil continues to dry, they emerge less frequently. They will continue this pattern throughout the summer until arid conditions or low temperatures will cause them to remain in their burrow. During these periods, they may preserve moisture by coating themselves with secretions from their skin while they wait for favorable conditions to reappear in the spring.

As a result, spadefoot toads may spend nine months of the year underground, not eating, drinking or defecating. Spadefoot toads are known to live up to 13 years in nature. Thus, they may spend over 9 years underground in their burrows buried alive.

The caller seemed quite interested by the life history of spadefoot toads. One part of the conversation that we didn't get into was the differences between frogs and toads or the myth that toads cause warts. That could have taken much longer to explain.