While the arctic tundra does not house much flora, it is home to a surprising amount of fauna. Although there are only 48 species located in the arctic tundra, there is an abundance of each species. Like most biomes, there is an ample number of insect species. These include black flies, deer flies, biting midges, mosquitoes, grasshoppers, and a type of arctic bumblebee. The predators of the arctic tundra include wolves, wolverines, arctic foxes, and polar bears. These carnivores prey on primary consumers like shrews, hares, lemmings, rodents, squirrels, caribou, musk oxen, and deer. Along with these organisms are various migrating birds like ravesn, snow buntings, falcons, loons, sandpipers, terns, gulls, and snowbirds. All of these organisms have adapted to breed and raise their young quickly in order to survive the cold. Most of the mammals have layers of fat for insulation. As well, some animals hibernate or migrate to escape the cold.