In August, warnings from poison experts began to circulate: A toxic species of toad was unusually populous in the Phoenix area.
“Leave these toads alone and be sure to keep your dogs away from them,” Maureen Roland, managing director of the Banner Poison Center, warned in an announcement the center issued last month.
The Sonoran Desert toad, or Colorado River toad, is found across the Southwest and has glands with psychoactive toxins strong enough to kill a dog. At more than half a foot long, it's the largest toad native to North America — one reason why its venom is so strong. The toxins can pose a threat to humans, too, the center wrote, though mostly only if they are ingested.
But while poison centers worry, herpetologists have been celebrating. It has been years, they say, since the toads have been seen in the Phoenix area in such numbers. Their absence had stoked worries about the impact of climate change on their population. Now it seems the toads are thriving once again.
Brian Sullivan, a professor and herpetologist at Arizona State University, has been monitoring Sonoran Desert toads in Phoenix for the past four decades. It has been several years, Sullivan told Phoenix New Times, since he has seen the toads active at his research site out by the Carefree Highway in north Phoenix. A series of unusually dry monsoon seasons had kept the creatures underground, where they typically hide out unless there is sufficient rainfall for them to emerge.
“They hadn’t successfully bred there for four years,” he said.
The summer rains have revived them. This monsoon season has caused bugs, poisonous mushrooms, and other amphibians to flourish in Phoenix. At Sullivan’s site, new Sonoran Desert tadpoles are abundant, he says, and toads that have been buried away are active again.
It's not clear, though, if this summer will ensure more of the toads in the long run. For now, Sullivan said, this year has only “kept them from the brink.”
Heather Bateman, a field ecologist at ASU who specializes in amphibians and reptiles, can confirm: “It’s kind of an amazing year” for toads, she told New Times.
Bateman argues that, while you should probably keep your dogs away from the toxic toads, the creatures pose little danger to humans unless they are literally in your mouth. It is safe to pick them up, she said, though she advised hand-washing afterwards.
It is also true that Sonoran Desert toads are sometimes illegally poached by humans in order to extract their toxins, which can be used and sold (illegally, at least in the United States) as an intense hallucinogenic drug. In 2019, Sonoran Desert toad venom was hailed as “the new trendy hallucinogenic.”
Has Arizona's toad black market gotten busier this summer, given the toads' abundance?
Not that the state of Arizona has yet noticed. “There has been no increase in the reported illegal take of Sonoran Desert Toads,” Scott Fischer, manager of the Arizona Game and Fish Department's law enforcement branch, wrote in an email to New Times.
Sullivan said that, in his years observing the toads, he has not seen a noticeable impact on their population levels from poaching. More worrisome for the creatures, he said, are impending changes in climate.
“It's getting worse — because we're going to have more dry monsoon summers in the next 50 to 100 years," he said. "And that's the big question: will they be able to weather that?" In the long run, it may drive the toxic toads out of Phoenix.