Scout: It's Raining Toads
Summer showers bring forth tadpoles at Monahans Sandhills.
By Elaine Robbins
Every Sunday for about 15 years, Bill Loos has trekked across the Sahara-like landscape of Monahans Sandhills State Park. A keen observer and photographer, he is familiar with the shifting vistas of the sweeping sand dunes, some of which tower as high as 70 feet. But one morning last June, Loos noticed an unusual sight during his weekly fitness walk: a slimy black goo that covered one of the shallow rainwater ponds that had collected between the dunes after heavy rains a few weeks earlier.
As he got closer, Loos realized that the substance was actually a huge wriggling mass of tadpoles. "I had to do a double take," says Loos. "I'd seen tadpoles, but I'd never seen them that thick – just thousands of them."
What was this explosion of tadpoles in the desert? Some kind of biblical plague?
Actually, the phenomenon is not all that unusual, according to Burr Williams, director of the Sibley Nature Center in Midland.
"It probably happens every four years. Every time we get a big rain – enough to fill up a playa – you'll find a large number of tadpoles."
The toads are uniquely adapted to the short rain cycles of the Mescalero Sands, an ecosystem that extends from southwest New Mexico down to Monahans.
"The adult toads can remain buried in the moist sand for a whole year between breeding cycles," explains Andy Price, TPWD herpetologist. "When rain comes, there's a cue – whether it's rain hitting the ground or something else – that causes them to come up and start breeding right away."
Their offspring need to mature quickly, before the ephemeral pools dry up. "Tadpoles have an accelerated development process and can develop in as little as two weeks," says Price.
Loos returned over the next few weeks to see how his tadpoles would fare. "It started to dry up over the course of weeks," he says. "It was a race to see if the toads were going to mature to survive. In the end, a good number made it, and many didn't."
This summer, after heavy rains, the survivors will dig out of the desert sands and begin the cycle again. During their mating period, West Texans will be treated to a sweet summer lullaby. "That's one of the lovely sounds out here in West Texas in the night after a big thunderstorm," says Williams. "You hear the sound of toads singing, sometimes up to a mile away, as they sort out who meets who."
For more information, visit <www.sibleynaturecenter.org/photoessays/toads/index.html>.