The common raven (Corvus corax) is a large bird in the family Corvidae, found all throughout the Northern Hemisphere. It is the most widely-distributed corvid species. Growing up to 28 inches in length and with a maximum wingspan of 60 inches, it is among the largest corvids as well. It is believed to have evolved during the Chibanian age of the Pleistocene epoch, around 400,000 years ago. This is one of the most intelligent birds. Due to its adaptability and widespread habitat, the International Union for Conservation of Nature considers it a species of least concern. There are currently eight recognized subspecies, though some ornithologists believe there may be more:
- Corvus corax principalis, northern raven, found in Canada, Alaska, and Greenland
- Corvus corax sinuatus, western raven, found in the southwestern United States and Central America
- Corvus corax varius, North Atlantic raven, found in Iceland and the Faeroe Islands
- Corvus corax tingitanus, North African raven, found in Northern Africa including the Canary Islands
- Corvus corax corax, North Eurasian raven, found from Europe to the Caucus region and as far east as Lake Baikal
- Corvus corax subcorax, South Eurasian raven, found in southeastern Europe and the sub-Himalayan region
- Corvus corax tibetanus, Tibetan raven, found in the Himalayan Mountains
- Corvus corax kamtschaticus, Kamchatka raven, found in northeastern Eurasia from Lake Baikal eastward
