Farewell Froggy, the Age of Ribbit is Nearing an End

Amphibians are disappearing horrifyingly fast worldwide, with a third of species imperiled. But they're disappearing even faster than believed in the US—and probably worldwide (more on that below)—according to the first ever analysis of the rate of population losses among frogs, toads, salamanders, and newts.

New Study: Common Pesticides Kill Frogs on Contact

To me, there are few more comforting sights on a farm or in a garden than a frog hopping about amid the crops. Frogs and other amphibians don't just look and sound cool—they also feast upon the insects that feast upon the plants we eat. These bug-scarfing creatures are a free source of what is known as biological pest control.

But modern industrial agriculture doesn't have much use for them. It leans on chemistry, not biology, to control pests—and in doing so, it's probably contributing to the catastrophic global decline of amphibians, a natural ally to farmers for millennia. The irony is stark: In industrial agriculture's zeal to wipe out pests, it is helping to wipe out those pests' natural predators. The latest evidence: a new study showing that exposure to common pesticides at levels used in farm fields can kill frogs rapidly.

The Frog of War

Darnell lives deep in the basement of a life sciences building at the University of California-Berkeley, in a plastic tub on a row of stainless steel shelves. He is an African clawed frog, Xenopus laevis, sometimes called the lab rat of amphibians. Like most of his species, he's hardy and long-lived, an adept swimmer, a poor crawler, and a voracious eater. He's a good breeder, too, having produced both children and grandchildren. There is, however, one unusual thing about Darnell.

He's female.

Genetically, Darnell is male. But after being raised in water contaminated with the herbicide atrazine at a level of 2.5 parts per billion—slightly less than what's allowed in our drinking water—he developed a female body, inside and out. He is also the mother of his children, having successfully mated with other males and spawned clutches of eggs. Recently he was moved to an atrazine-free tank and has turned lanky, losing the plump, pincushion look of a female frog. But last March, when UC-Berkeley integrative biology professor Tyrone B. Hayes opened him up to take a look, Darnell's insides were still female. "He still has ovaries, but there's no eggs in them," Hayes told me the next day as we stood watching the frog, who swam over and inspected us soberly, then turned and flopped away.