Nearctic realm

The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico.

The Canadian Shield bioregion extends across the northern portion of the continent, from the Aleutian Islands to Newfoundland.

The Northern Mexico bioregion includes the mild-winter to cold-winter deserts and xeric shrublands, warm temperate and subtropical pine and pine-oak forests, and Mediterranean climate ecoregions of the Mexican Plateau, Baja California peninsula, and the southwestern United States, bordered to the south by the Neotropical Trans-Mexican Volcanic Belt.

Many large animals, or megafauna, including horses, camels, tapirs, mammoths, mastodons, ground sloths, sabre-tooth cats (Smilodon), short-faced bears and the American cheetah, became extinct in North America at the end of the Pleistocene epoch (ice ages) in what is called the Quaternary extinction event.

[2] The Holarctic has four endemic families: divers (Gaviidae), grouse (Tetraoninae), auks (Alcidae), and the waxwings (Bombycillidae).

The Nearctic realm (in green)
Ecoregions of the Nearctic realm, color-coded by ecoregion . Note that much of the coast, south, and southwest Mexico and the southern half of Florida in the United states are considered part of the Neotropic realm .