Cervids, or deer, are members of Cervidae, a family of hoofed ruminant mammals in the order Artiodactyla. They are widespread throughout North and South America, Europe, and Asia, and are found in a wide variety of biomes. Cervids range in size from the 60 cm (24 in) long and 32 cm (13 in) tall pudú to the 3.4 m (11.2 ft) long and 3.4 m (11.2 ft) tall moose (example pictured). The fifty-four species of Cervidae are split into eighteen genera within three subfamilies: Capreolinae (New World deer), Cervinae (Old World deer), and Hydropotinae (water deer). Extinct species have also been placed into Capreolinae and Cervinae. More than one hundred extinct Cervidae species have been discovered, though due to ongoing research and discoveries the exact number and categorization is not fixed. (Full list...)