In the days before they used modern equipment, coal miners sent canaries into mine shafts. If the birds lived, the miners knew the air was safe to breathe. They could then enter the mine.

Today, other animals give us clues about dangers we can’t see. Amphibians (animals that live in water and on land) are a good example. In the past few years, strange things have been happening to them. The causes for what has happened affect not only the animals, but people as well.

Why Are There Fewer Frogs?

Scientists found that the number of frogs across the country has been going down. Then students from a Minnesota school made a weird discovery. As part of a nature-studies class, students from the Minnesota Country School went hiking. They were near Henderson, Minnesota, in the southwestern part of the state.

The students found frogs that looked very unusual. Some were missing legs or eyes. Others had extra legs! Since the students’ discovery, people in more than two dozen states have reported finding similar frogs. Scientists wondered if water pollution was the cause.

What We Now Know

The area in Minnesota where the frogs were discovered is not the kind of place in which you’d expect to find water problems. Water in the clean rural area seemed clear and drinkable. Even so, scientists believe that the water holds the secret to what damaged the frogs.

What’s in the Water?

Scientists and local officials have tested ponds at 50 locations around the state. They suspect that chemicals from pesticides may be polluting the water. Or the villains may be algae or parasites that live in the water, the scientists say.

Whatever the cause, people in Minnesota can be grateful that frogs have sensitive skins. Their sensitivity to pollution is an early-warning system for people.

Salamanders Warn Us Too

Salamanders are early-warning systems too. Like frogs, they are sensitive to their environment. And their numbers, in many places, are also falling. One kind of endangered salamander lives in Barton Springs, Texas, near Austin.

Recently, poisonous chemicals such as lead, gasoline, and arsenic have been found in salamanders homes. The chemical levels are not high enough to harm people. But steps are being taken to protect the water. The salamanders and the 35,000 people who drink the water in Barton Springs may share a healthy future.

Get an update on the Minnesota frogs at Minnesota New Country School Frog Project Web site:

Scholastic News, Senior Edition, 12/8/97