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, including recently, 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. Though not as adaptable as more generalist canid species, wolves have thrived in temperate forests, deserts, mountains, tundra, taiga, grasslands, and even urban areas. Though once abundant over much of Eurasia and North America, the gray wolf inhabits a very small portion of its former range because of widespread destruction of its territory, human encroachment, and the resulting human-wolf encounters that sparked broad extirpation. Even so, the gray wolf is regarded as being of least concern for extinction according to the International Union for Conservation of Nature, when the entire gray wolf population is considered as a whole.