The gray wolf or grey wolf (Canis lupus), often known simply as the wolf, is the largest wild member of the Canidae family. It is an ice age survivor originating during the Late Pleistocene around 300,000 years ago. DNA sequencing and genetic drift studies reaffirm that the gray wolf shares a common ancestry with the domestic dog (Canis lupus familiaris). Although certain aspects of this conclusion have been questioned, the main body of evidence confirms it. A number of other gray wolf subspecies have been identified, though the actual number of subspecies is still open to discussion. Gray wolves are typically apex predators in the ecosystems they occupy.