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Malformed Frogs by Susie and Katie

We love frogs. When we were growing up, we tried to catch frogs behind our house. But usually they hopped right through our fingers! Recently we noticed a lot of the frogs in our pond had funny looking legs. That got us wondering: What's causing the malformations at our frog pond?

What did we do?
First we studied frog biology. Then we looked at what scientists say causes frog malformations. We found three main causes: too much UV light from the sun, chemical pollutants, and parasites. Each cause shows up as a different kind of malformation. We got a bunch of neighbor kids together and started collecting as many frogs as we could. We sorted the frogs into categories: healthy, malformed on one side of their body (asymmetrical), and malformed on both sides of their body (symmetrical).

What did we find out?
We found a lot of malformed frogs! We caught 15 malformed frogs and 30 normal frogs. That means 33% were malformed, and that's a lot! Then we found out almost all of the malformations affected the frogs' back legs on one side of their body only. That's a pretty strong sign that these malformations were caused by parasites. We couldn't tell why there seemed to be a parasite problem this year and not other years.

What can you do?
  • Ask your teacher's help in setting up an aquarium for tadpoles. Observe the tadpoles carefully each day, and write down the changes you see. How many days does it take for the legs to appear, and the tail to disappear?
  • Ask your local Department of Natural Resources (DNR) office if they are conducting frog studies. If you live near a frog pond, ask how you can help collect information about the kinds of frogs living in your pond, and whether the pond water is healthy for the frogs and other wildlife.
  • Go online and find samples of different frog calls (croaks). Then listen for calls at a pond or marsh for one hour three times during the spring and early summer. Learn how to tell the calls apart, and match the calls to the kinds of frog or toad at your pond.
  • Use this environmental science investigation as a science fair project idea for your elementary or middle school science fair! Then tell us about it!
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