EYES
Like most predators, polar bears have eyes that face straight forward and are spaced apart to provide binocular vision. Vision range is not very well studied, as some have reported poor vision while others would agree that vision can vary depending on the bear. There seems to be general agreement that it's similar to that in humans, but better in some aspects (such as night/low-light vision) and worse in others (faraway, non-moving objects) (Woodford, 2005). However, they also have a protective nictitating membrane that helps protect their eyes against snow blindness and when underwater. This membrane is like a third eyelid, and filters UV light so that light reflected off the snow is not so harmful to the polar bear's eye.
EARS
Naturally, the ears assist the polar bear in hearing as well as maintaining balance. Hair cells are important for both functions; the perception of sound is only due to the bending of stereocilia on hair cells, which causes a depolarization and consequent action potential that is perceived by the brain as noise. They can also be found in the vestibular and otolith organs, which are responsible for detecting linear/angular movement and acceleration.
Polar bear hearing is more attenuated to higher frequency sounds, as one study found that polar bears were most sensitive in the 11.2 kHz to 22.5 kHz range (Nachtigall et al., 2007) - in comparison, humans can hear from about 20 Hz to 20 kHz (Cochlea.org). Their ears also face forward, and are particularly small in size - an adaptation that evolved due to the frigid nature of the Arctic. To reduce the metabolic costs of staying warm, Ursus maritimus have developed short extremities in comparison to other bears. Their tails are very short as well for the same reason! MOUTH
Polar bears have 42 teeth that highly reflect their carnivorous, predatory lifestyle. Consisting primarily of incisors, canines, premolars and molars, their teeth are similar to that of their bear relatives as well as other carnivorous mammals. Yet despite their genetic closeness to brown bears, polar bears have developed differences since the two lineages split. In particular their cheek teeth (molars and premolars), which help grind food and are useful in omnivorous animals, are much smaller in size while carnassials and canines are much larger and longer (Amstrup et al, 2003). This is likely due to the fact their food source is meat and protein much more so than it is fibrous vegetation, so they don't necessarily need the teeth that help other bears chew plant matter. Instead, they need teeth that can help them grip and tear the meat off of wriggling prey.
Unfortunately at this point, there isn't much research on the tasting ability of the polar bear and its role in diet preference. NOSE One of the most, if not the most, important sensory organs for the polar bear is their nose. Their olfactory sense is very sensitive, and it's believed that their sense of smell is much better than their vision or hearing. This allows them to locate land prey very well - up to 1 km away and 1 m under the snow! (Seaworld).
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