Florida Panther
I know what you’re thinking: There’s no way a house cat could take down a panther. But sometimes warfare is biological. In 2008, a team of researchers reported that an outbreak of feline leukemia virus in the endangered Florida panther could be traced back to domestic cats; the outbreak killed five panthers—a significant hit, considering there are barely 200 left in the wild. While feline leukemia alone may not be the death knell for panthers, this is how extinction sometimes happens, with the compounding effects of different threats.
