Skunks
Top 1 in Top 10 World's Most Solitary Animals
Skunks come in a variety of varieties, and they tend to live alone most of the time. This makes sense since when skunks feel threatened, agitated, or attacked, they release a potent odor that repels any animal within a few meters. They like to live their lives as free, independent individuals, unlike other mammals, even those from the same family.
Skunks, especially females, may share niches in cooler areas, though. Male skunks can mate with multiple females, but they are doomed to death after that. Female skunks remain with their units for a year once they produce offspring and are protective of them.