Danny, mange is not always fatal in yotes. I have caught far to many that have the black scars on their ears and on their legs, and also caught them where they were growing new fur in areas that had been bald. Now in fox, I believe it is 100% deadly. It seems where it is more deadly in coyotes is when yotes with mange raise pups. It seems that those pups never have a chance, they only get to about ten or so pounds, and are usually totally bald, look like blue rats I have never seen any recovery from it at that extent.