The phrase "female wolf" refers to a female member of the wolf species. It means a wolf that is biologically a female, similar to how some animals have males and females. Full definition
Eileen Hebets of Cornell University introduced 81 sexually immature female wolf spiders to a variety of sexually mature males in the laboratory. (scientificamerican.com)
A mature female wolf comes into estrus once a year. (wolf.org)
There are queen bees, alpha gorillas, and male - female wolf pairs that dominate the pack. (entrepreneur.com)