Another consideration:

DEADLY DISEASE A disease might also cause the mutations. The disease is
carried and spread by a tiny worm.
The worm is a parasite, a plant or animal that lives off of other creatures. If
a worm enters a frog's body, it can give the disease to the frog. The disease
causes extra or missing limbs in the frog's young.
The disease-carrying worm seems to be spreading. As the worm moves into new
lakes and ponds, it brings the disease with it. That means more frogs can catch
it.
Frogs are not the only creatures that can catch the disease. Some other
amphibians, including toads and salamanders, can get it as well.


kathy :-)
A HREF="http://www.onceuponapond.com/"Once upon a pond/A