Some of its distinct subspecies also have common names of their own.
It is a variable species with several ecotypes, some of which are distinct subspecies.
When demes are isolated for a very long time they can become distinct subspecies or species.
As of early 2008, the following good species and some rather distinct subspecies are listed:
European population, which formed as a distinct subspecies probably during the last ice age.
They were in fact a separate variety of Jet, perhaps a distinct subspecies.
The California population might be considered a distinct subspecies or even species, brevipennis.
The latter seems to be a local morph rather than a distinct subspecies however.
It comprises three distinct subspecies groups, all of which may be separate species.
The Wood bison is a distinct subspecies that almost became extinct in the 20th century.