Wolves are the largest member of the dog family, since the extinction of the comparatively massive dire wolf around 8,000 years ago. Dogs and wolves are so closely related that interbreeding could be a problem where wolf territories overlap human settlements. There are 37 sub species of wolf.
The wolf used to be the most widely distributed land mammal, but due to hunting and loss of habitat their previous range has been significantly reduced. Fittingly, the animal that has now taken over this title is the closely related red fox.
Contrary to survival instincts, larger prey species stand a much better chance if they stand their ground against a pack of wolves. Wolves depend on wearing down their prey before finishing them off, utilising their impressive stamina. In finishing off their prey, wolves have a fantastic bite strength, equating for around twice that of a German shepherd.
Wild wolves were reintroduced to Yellowstone from Canada in the 1900s. They proved to be such success that they have subsequently been removed from the Federal List of Endangered and Threatened Wildlife.
Wolves are such iconic species that their name has been used for other animals' nicknames. The giant otter is called the "river wolf" and killer whales are the "wolves of the sea", both species attained this moniker due to their pack-hunting behaviour.