

The Eastern hellbender salamander may not be a looker. But its sensitivity to pollution and changing water conditions makes the creature a useful indicator for water quality in rivers and streams.
(Image credit: Rick Callahan/AP)
The Eastern hellbender salamander may not be a looker. But its sensitivity to pollution and changing water conditions makes the creature a useful indicator for water quality in rivers and streams.
(Image credit: Rick Callahan/AP)