Why Do Bears Hibernate

Hibernation: Hibernation is a sleeping state, which lasts for long periods of time. ANimals like bears, eat lots before entering hibernation so that their body has enough fuel to live. They enter hibernation during winter, because during winter there is no food for them to eat, and if there is it is very scarce.

The bear have evolved along time ago and now there is only eight species existing. They evolved from early canids during the late Oligocene and early Miocene, about 25 million years ago. The earliest ancestors where the Dormaalocyon Latouri. An intermediate ancestor was the short faced bear, very similar to the modern day bear. It lived through the pleistocene period. It grew to thirteen feet long and was a herbivore. The ancestors to the modern day bears lived in the same climate and ate the same things. The modern bear contrast from the ancestor because the ancestor was more skinny and was smaller, and it was more cat like. The eight species of bear that still exist. They are the Polar bear, Brown bear, American black bear, Asian

The grizzly sheds the thick part of their coat during the summer. The coat also protects the grizzly bear from insects or any types of bugs. The grizzly bears have a very large home range that they will roam through. The grizzly bear also spend hours of the day walking around, but that is common for grizzly bears. The wear in the temperate rainforest is sunny and sometimes rainy. When the grizzly bear needs to move quickly through their habitat it can be done so at a speed of 30 miles per hour. The mating season for grizzly bears start in mid-May it continues until the middle of July. Grizzly bears can live in the wild up to 30years. They can also die at the age of 25. Grizzly bears can be found in woodlands, forests, alpine meadows and prairies. They prefer to be around streams or rivers. Grizzly bears are mainly solitary, except for mothers and their cubs. Grizzly are known to meet up at a river or a stream. Grizzly bears are also very strong swimmers. Grizzly bears use sound, movement, and smells to communicate with each other. Grizzly bears happen to groan and moan to get each others attention. Grizzly bears also rub their bodies on trees so they scratch their self. Throughout the summer grizzlies build up fat by eating as much

“Black bears are not true hibernators” according to Nation Geographic. Black bears have several reasons they may leave their den during the winter months, mainly if they do not have enough food to last the winter, they will leave and search for more. If the weather is warmer like down in Florida and Louisiana, they don’t necessarily have a winter. They will remain in their dens if they give birth, presumably for the safety of the cubs.

For hibernation, they need to eat a lot of hard and soft “mast” in autumn [3]. Brown bears are also omnivorous, and eat mostly leaves, fruits, nuts, and seeds, and less often insects, small mammals, and fish [4]. They also need to eat a lot of hard and soft mast in autumn to prepare for hibernation.

The female bear will stay with her cubs for one and a half to two years. The mothers will teach cubs important life survival skills and then leave them to have another litter of cubs (American Black Bear, 2015). Males will leave hibernation early to search for a mating partner, while females do not. Another way males and females are different is there physical appearance. Male skulls are 10% larger than females (Ballard,

Grizzly bears have had to adapt when the weather is off like having a warm winter it sets their internal clock off to where when they should be hibernating they are still out or cold weather comes late they are already awake from hibernation or cold weather comes to to early and they aren’t hibernating. They also have to deal with man made disasters like oil spills or fires, both can kill bears and kill what they eat like fish which could then kill the bears if they can not eat enough food because their immune system will deteriorate and kill them. Grizzly Bears are divergent because recent studies have shown that some grizzly bear’s mothers are polar bears and fathers are grizzly bears. This means that the fathers travel long distances to mate with mother polar bears. The most recent studies have suggested that they have been divergent from about 150,000 years ago. (Tia Ghose) Past research revealed that brown bears on ABC Islands, off the southeastern coast of Alaska, had mitochondrial DNA that look just like polar bear DNA.(Mitochondrial DNA comes only from the mother and is carried in the cytoplasm in the cell’s energy-making structures called mitochondria.) (Tia

Rattlesnakes are even known to move around during extended warm periods during winter months, especially if they hole up in a stump or other location that can be warmed easily by sunshine. Snakes do not actually hibernate, rather they become less active during cold weather. It is called

Each species of bear eat certain foods more than other bears." (Alina Bradford) During summer bears can eat a whole day to fatten up for hibernation. Bear's diets depends on what food is available for the season. Since there's a lot of plants and animals, bears can have enough food and they even eat grass. "

The water bears live all over the world from the deepest sea to the Himalayas. Most of the water bears live in fresh water, often in wet or moist habitats that are subject to frequent periods of drying and then rewetting such as the moss on a roof or algae in the gutters. Other areas include hot springs, glaciers, lichens, leaf-litters. Their ability to form a “tun” allows them to be blown around the world by the wind. The water bears enter a cryptobiotic phase in environments with intermittent moisture that allows them to survive conditions such as drought, low oxygen, salinity changes, or extreme temperatures.

The average temperature of a polar bear is 37°C, they are able to maintain this temperature by the thick  layer of fur they have, they also have a tough hide and a insulating fat layer. This insulation is able to keep the polar bear warm in temperatures that drop to -37°C. However as polar bears have a very thick layer of fat they can overheat and can die because of this, so the way they are able to keep cool is they do not travel for too long at a slow pace. Doing this stops the polar bear from overheating. If there is excess heat it will be released through the nose, ears, muzzle, footpads, thighs and shoulders as these areas do not have any fur covering it and these areas they have blood vessels which are located close to the skin. Another thing they can do to cool down

The polar bear is the largest known land animal that eats meat. With black skin, and light reflecting fur, it is capable of a lot of things with its adaptations. Adult polar bears can weigh over 1,400 lbs and can grow up to 10 feet tall. With this, they can use their unbelievable strength to catch prey like sea lions, walruses, etc. Polar bears have adapted to swim up to 100 miles (6 miles an hour). Though, you may think they are cold most of the time; they’re not. Polar bears tend to overheat more than getting too

Asiatic black bears are primarily nocturnal feeders and sleep in a tree hole or in a cave during the daytime, but they do sometimes forage diurnally. During the autumn, their nocturnal activity increases("Asiatic Black Bears", 2004). They shift their ranges in early autumn in order to obtain native broadleaved

Animals of the tundra have had to adapt to the long cold winters and to having to raise their young quickly in the summer. Some other adaptations of animals include thick insulating cover of feathers or fur; large, compact bodies; pelage and plumage that turns white in the winter and brown in the summer; the ability to accumulate thick deposits of fat during the short growing season; hibernation; and migration. Some of the animals that are found living in the tundra are lemmings, voles, caribou, artic hares, squirrels, artic foxes, wolves, polar bear, ravens, snow buntings, falcons, loons, ravens, sandpipers, terns, snow birds, mosquitoes, flies, moths, grasshoppers, black flies, artic bumble bees, cod, flatfish, salmon, and trout. Some of these animals are shared with other neighboring biomes but some are only home to the tundra. The tundra is the simplest biome in terms of species composition and food chain. The neighboring biome of the tundra is the boreal forest (taiga).

Not all animals migrate during the winter; such as: birds,fish, whales and sea turtles. On the other hand, most mammals, and some reptiles like the tortoise prefer to sleep during the whole winter, which will usually last up to five to seven months. These months vary from animal to animal; this is called hibernation. Ubeda claims in his article that, hibernation is a deep sleep in which an animal's body temperature drops to just above the temperature of the outside world to conserve as much energy as possible (Ubeda). Hibernation by larger animals, such as, the bear or mountain lion usually occurs during the winter in large dens. On the other hand, if the animal is smaller like a squirrel or a rabbit, hibernation will take place in a small hole or a tree. One reason why hibernation occurs is because food is scarce and harder to achieve, so animals need to conserve all their energy. In Grabianowski’s article, he claims that an animal starts hibernation by slowing their heart rate down (which allows their body temperature to drop) (Grabianowski).