Freaky Frogs

A healthy pond frog Frogs with no hind legs, frogs with five hind legs; what started with school children collecting frogs for their school biology projects turning up an inordinate percentage of frogs with deformities in the mid-nineties has since became a nationwide research project into why so many amphibians throughout North America (and in Asia, Europe, and Australia as well) are turning up deformed.

The first suspect was thought to be ultraviolet radiation. While it was shown that increased exposure to UV radiation can cause abnormalities, it couldn’t explain the extra limbs found on many frogs.

The next suspect was chemical pollution, but isolating a specific chemical as a cause to the specific types of deformities proved difficult and inconclusive.

It has finally been determined that the types of leg deformities found in frogs can be traced to parasitic infections from worms. Microscopic parasitic worms called trematodes that grow in snails and eventually end up planting themselves in the spots in tadpoles where legs would normally develop.

Okay, that’s a little gross, but the next question is why these parasites are suddenly more prevalent.

On Monday a team of researchers announced that research now shows conclusively that algae blooms in lakes and ponds caused by nitrogen and phosphorus runoff from farming and ranching start a chain reaction that, in all too many cases, end up as deformed frogs.

I think our friend Kermit the Frog says it best: It’s not easy being green.

Sources and Further Reading:
Planet Ark
Scientific American