What do you call two or more groups of animals that are not subspecies of the same species, but who can mate and produce fertile offspring?
Closely related.
For example: Tigers and Lions are closely related members of the feline ‘family’ that can produce fertile offspring.
Another example: Coyotes and Wolves are closely related members of the canine ‘family’ that can produce fertile offspring.
Words are, and always will be, imprecise reflections of reality. They are not themselves real, nor do they dictate reality.
Exactly!