Brown Bears Vs Polar Bears

Both polar bears and brown bears are carnivorous animals, but they live in two different ecosystems. Polar bears (Ursus maritimis) lives in cold/arctic environments such as the northern coasts, Alaska, Canada, Norway, and Russia (“Polar Bears and Brown Bears”, n.d.). Brown brown bears (Ursus arctos) lives in temperate areas. Some temperate areas are Canada, United States and across northern Europe and Asia (“Polar Bears and Brown Bears”, n.d.). The fur of the polar bear is snow white/ yellow while the fur of the brown bears is brown. These two species might seem different because of their phenotype and living environments, but they are genetically closely related. Even though we know that the polar and brown bears are genetically closely relate,

According to Shiping Liu and Eline D. Lorenzen (2014), they stated that “it was the longest interglacial in half a million years and lasted almost 50 kyr” (Liu Shiping; Lorenzen D. Eline, 2014). This indicated that the Marine Isotope Stage (MIS) have lasted for really long time and it might have caused the evolutionary relationship of the brown and polar bears to occurred. During this period of time, it had melted many glaciers which had allow the brown bears to colonize to other areas. During the MIS, some brown bears were stress-tolerant and willing to try the new arctic habitat while less tolerant brown bears chose to leave (“Polar Bears and Brown Bears”, n.d.). As times goes on, the brown bears that chose to stay adapted to the arctic habitat and learned to catch seals and fishes and have more fat behind their fur in order to stay warm in the new habitat. Gradually, their fur changed to a snow-white color which was common in the arctic habitat. Some answers still remain unanswered such how long did it take for the polar bears to diverged from brown bears and what could have happened during that time of