to this biome, occurring as frequently as every 50–100 years in some parts. Adaptations to conditions Humans Humans living in the Arctic region generally rely on warm clothing and buildings to protect them from the elements. Acclimatization, or the adjustment to new conditions, appears to be the most common form of adaptation to cold environments. No genetic advantage has been found when different people groups or races are compared. There is no evidence that fat is grown in response to cold, although its presence is advantageous. Amazingly, most people living in the Arctic region live a lifestyle very connected to the environment, spending significant time outside and depending heavily on hunting and fishing. Other animals Animals that are active in the winter have adaptations for surviving the intense cold. A common example is the presence of strikingly large feet in proportion to body weight. These act like snowshoes, and can be found on animals like the snowshoe hare and caribou. Many of the animals in the Arctic are larger than their temperate counterparts (Bergmann’s rule), taking advantage of the smaller ratio of surface area to volume that comes with increasing size. This increases the ability to conserve heat. Layers of fat, plumage, and fur are also very effective insulators to help retain warmth and are common in Arctic animals including polar bears and marine mammals. Some animals also have digestive adaptations to improve their ability to digest woody plants either with or without the aid of microbial organisms. This is highly advantageous during the winter months when most soft vegetation is beneath the snow pack. Not all Arctic animals directly face the rigors of winter. Many migrate to warmer climates at lower latitudes, while others avoid the difficulties of winter by hibernating until spring. Although these options might seem to be easy solutions to the difficulties of surviving an extreme environment, both are very expensive in terms of energy and risk of predation. Plants One of the most serious problems that plants face is ice crystal formation in the cells, which results in tissue death. Plants have two ways to resist freezing: avoid it or tolerate it. Plants have several avoidance mechanisms to prevent freezing. It can build up insulation, have its stem close to the ground, use the insulation from snow cover, and supercool. When supercooling, water is able to remain in its liquid state down to (compared to