Rabies and distemper have been ruled out, but experts have not solved the mystery of Redding's dead skunks.

About 60 dead or dying skunks - and a fox and a raccoon - have been found in Redding since mid-February.

Having ruled out distemper and rabies, University of California, Davis, experts are looking at toxic substances or parasites as the cause of the animal deaths.

To get to the bottom of what is killing the skunks, local animal control officials are working with the state Department of Fish and Game and experts from the UC Davis Center for Vectorborne Diseases.

"It's important to identify what is causing this unusual die-off, because the skunk can be a sentinel species that often alerts us to environmental health problems," veterinary researcher Janet Foley said in a news release.