The Frog Deformity Problem

by
Philip Bell
KIE Developer

The Discovery

Since 1992, scientists have been finding more and more frogs that are deformed. During the summer of 1995, middle school students at the Minnesota New Country School went on a field trip. As they hiked they saw many frogs hopping about. The students looked closer and noticed that many of the frogs were deformed. For some reason the frogs were not developing correctly.

(FROG PICTURE COURTESY OF DR. STAN SESSIONS)

Click the following link to read the full description of their discovery.

The Minnesota New Country School Frog Project
(AFTER YOU ARE DONE COME BACK TO THIS PAGE BY PRESSING THE BACK BUTTON)

Using the Internet, the students in Minnesota spread the word about the frogs they found. Since then, people have found deformed frogs in different parts of the country. Scientists are still trying to figure out what's going on.

What Do the Deformities Look Like?

Frogs are being deformed in a number of different ways. Follow the links below to see the different types of frog deformities that have been found:

PICTURE FROM THE MINNESOTA POLLUTION CONTROL AGENCY
http://www.pca.state.mn.us/hot/frogs.html

What Kinds of Deformed Frogs Are They Finding?
(CLICK ON THIS LINK TO SEE THE DEFORMED FROG PICTURES)

Scientists Are Investigating Different Hypotheses

Scientists do not know for sure what is causing the frog deformities, but they do have a few ideas. Two of the most important hypotheses that scientists are exploring right now include:

The Parasite Hypothesis

A small PARASITE

called a TREMATODE burrows into a tadpole near where the legs will develop. This parasite gets in the way and causes legs to develop incorrectly.

The Environmental Chemical Hypothesis

Scientists believe an evironmental chemical in lake water could be causing frog deformities. This chemical might be similar to a HORMONE

that has been shown to affect limb development.

You will have the opportunity to learn more about these hypotheses in later WISE projects. Do you think there might be other hypotheses to consider?

Deformed Frogs in the News (optional reading)

The frog deformity problem has been featured in the newspapers and on several news programs. The following are links to news transcripts and articles about the deformed frog mystery:

Evidence Information

KEYWORDS	deformed frogs, science controversy, parasite, pesticide
SUBMITTER	Philip Bell