In August 1995, schoolchildren found deformed frogs in a wetland near Henderson, Minnesota. Some frogs had extra legs, others no legs at all. Some had missing or extra eyes, toes, or feet. And some also had problems with their internal organs. By the fall of 1996, there were over 200 reports of freakish frogs, from two-thirds of Minnesota's counties. Deformed frogs have since been found in 44 states.
Courtesy Minnesota Pollution Control Agency
A 1997 study raised frogs in the lab, mixing pure water with water from two Minnesota sites that had lots of deformed frogs. The more pond water that was used, the more likely the lab frogs were to be deformed. Water from sites with healthy frogs produced healthy animals in the lab. The scientific conclusion was, "There's something in the water." But what could it be? Since then, several researchers have been hunting for the cause.
Scientists have proposed several explanations for the deformities. It may be parasites, chemicals, ultraviolet light, or some combination of the three. Lab studies have shown that all of these factors, alone or in combination, can cause some deformities. But no single cause seems to explain it all. The research doesn't yet add up to a neat and tidy answer, so scientists continue to puzzle out the story.
Who cares about frogs? You should. If there's something wrong with the water, it may eventually hurt all of us. But it will hurt frogs first. Frogs have thin skins, and easily absorb any contaminants in the water. Frogs seem to be in trouble all around the world. There are more and more reports of deformities. And some species have disappeared, or no longer live in their old habitats. It's a wide-spread problem that may affect us all.