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Minnesota frogs sprouting eyes in all the wrong places
October 24, 1996
Web posted at: 5:30 a.m. EDTFrom Correspondent Rusty Dornin
SAN FRANCISCO (CNN) -- Frogs. They are already suffering through an unexplained worldwide decline in population. Now comes the case of the deformed amphibians from Minnesota.
Schoolchildren in Minnesota were the first to notice that frogs were turning up with extra legs, eyes and other out-of-place body parts. But soon reports of similar amphibian abnormalities in places as far apart as Vermont, South Dakota and Quebec, Canada, were coming to scientists' attention.
Just as with the global decline in frog numbers, there's no widely accepted explanation for the high number of frogs sporting more than their usual four legs and two eyes.
The most popular theories credit the phenomenon to ozone depletion or environmental toxins. But biologist Steve Ruth thinks he may have uncovered part of the puzzle 10 years ago in California.
Ruth studied similar hind-leg deformities in California frogs and salamanders. He concluded they were the result of parasites invading the skin of young frogs and tadpoles.
"The parasites were causing the deformities through blocking the development of tissues," said Ruth, who published a paper on his findings in 1990.
Minnesota researchers say parasites explain only part of the phenomenon in their state.
"It doesn't provide a plausible explanation, at least not to our satisfaction, about the other kinds of deformities ... like the missing eyes ... and the partial legs," Mark Gernes of the Minnesota Pollution Control Agency told CNN.
The mystery is not merely the property of concerned herpetologists and state employees.
The Internet is abuzz with interested people proposing their own theories on what has caused the frogs to go genetically haywire. One popular theme in Web discussions is that the frogs' problems, regardless of their cause, may foreshadow similar woes for humans.
Steve Ruth, however, is excited by the mystery, believing it is both important and solvable.
"This is the first time," Ruth said while playing with a frog sporting 12 limbs, "that something could be directly linked to the kinds of abnormalities in amphibians."
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