Ursa+Maritimus

Questions!!! 1. What is the Polar bears favorite food?!?! 2. Do polar bears have long life spans??! 3. What color are polar bears?!!?!???

Pol ar Bear


 * Genus Name: ** Ursus Maritimus
 * Class, Order, Family: ** Mammalia, Carnivora, Urisidae


 * Endangered Species Act:** The year it was assessed was 2008 and it is based on a suspected population reduction of less than 30% within 45 years due to a decline in area of residence, extent of occurance, and habitat quality. Polar bears rely heavily on sea ice in the water for their survival so large scale changes in the habitat are impacting the population. The climate change globally posses a considerable threat to their habitat. Recent modeling of trends for sea ice extent, thickness, and timing of coverage predicts dramatic reductions in sea ice coverage over the next 50-100 years. Over the past 50 years sea ice has declined considerably. Although all bear species have shown adaptability in coping with their environment, polar bears are highly specialized for Artic life. Polar bears show low reproductive rates but have long life spans. These factors make facultative adaptation by polar bears to significantly reduced ice coverage scenarios unlikely. During previous periods polar bears did not adapt to warmer climate. Due to their extensive generation time and the present greater speed of global warming, it seems highly unlikely that polar bear will be able to adapt to the current warming trend in the Arctic. If climatic trends persist polar bears may become extirpated from most of their range within 100 years.


 * Description of Habitat**
 * Location of Ecosystem:**

The currents that are effect the Polar Bears habitat are: Labrador, East Greenland, and Norweigen.
 * Physical Habitat features:**




 * Habitat:** Polar bears occur at low densities throughout their range and most of them are in shallow water areas near shore or where currents or upwellings increase biological productivity near ice areas associated with open water, polynyas or lead systems. Polar bears are not as abundant in the high central arctic over deeper waters of the polar basin. Seasonally, in the summer open water season in the Canadian arctic islands and Svalbard, and in recent years during the fall in northern polar bears are found in Alaska and Russian Chukotka. Polar bears are well-adapted to severe cold. Winter temperatures in the far north often plunge to -40° F or -50° F and can stay that way for days or even weeks. In January and February, the average temperature in the high Arctic is -29° F.


 * Migrartion Patterns:** They are animals which know no boundaries. They pad across the ice from Russia to Alaska, from Canada to Greenland and onto Norway's Svalbard archipelago.


 * Population: ** There are nineteen hypothesized subpopulations which number in total 20,000 to 25,000 bears. Considerable overlap of putative populations occurs and genetic differences among them are small. About sixty percent of polar bears live in Canada. The population of polar bears is decreasing.


 * Appearance:** The polar bear has a very unique appearance. Their fur helps them camouflage in the snow when trying to catch a prey. They’re fur isn’t actually white, it has no color, each strand of hair is a hollow tube that allows sunlight to go through to their black skin underneath. The sunlight reflects off of the polar bear to make it look white. They also have a layer of blubber and it can be up to ten cm. thick. Each paw is about thirty cm. wide and eighteen cm. long. A polar bear is different from regular bears, because it has a longer head, neck, and nose. Their long necks help them keep their head above the water. Polar bears have very small tails and their ears are tiny. The height of an average adult male when standing is about 8’10” and on all four legs is about 6’8”. The height of an average adult female is 6’5”, and on all four legs is 3’6”. The average weight of an adult male is 1000-1320 lbs. The average weight of an adult female is 660 lbs. For polar bears teeth, their Canines larger and longer than for other bear molars smaller than those of land bears; molars more for shearing; premolars more for biting than grinding
 * Reproduction:** Breeding for polar bears occurs in March until May, implantation is delayed until autumn, and birth generally occurs from late November to mid-January. Although some cubs are born in earth dens, most births occur in snow dens that may be occupied between five to six months during the maternal event. In Alaska the maternal dens are located on the offshore sea ice. Only pregnant female polar bears den for this extended period of time, during which time they rely on fat stores for energy and sustenance. The average litter size is less than two. Cubs depend on their mothers until after the start of their third year of life. Age of first reproduction is normally five to six years for females. These factors contribute to the low reproductive potential for the species.




 * Animal anatomy and physiology:** Polar bear anatomy is completely adapted to the environment in which it lives. A sturdy body, strong muscular legs, and large neck muscles help it survive. It has very large feet with a small amount of webbing between the toes, which makes it a powerful swimmer. A polar bear can swim 60 miles without pausing to rest. At an average speed of 6 miles per hour, that is 10 hours of constant swimming. It can dive to a depth of 15 feet and stay under for 2 minutes or so. When underwater, its nose and ears close up but the eyes stay open to search for prey. It has also been seen jumping 7-8 feet out of the water to catch a seal. The bottom of its paw is covered with dense fur, providing more traction when they are walking on ice. The front legs are very muscular and enable it to break into seal dens or flip seals out of the water. The bear can go weeks without food, yet the stomach is able to hold a lot so it is able to eat very large meals when it gets the chance. Its coat color ranges from white to a yellowish white, which camouflages the hunter. The fur itself is composed of two layers. One layer is a fine, white hair and the other is a layer of guard hairs. These hairs are hollow and help keep the polar bear buoyant. Its skin is black, making it so efficient at heat retention that it does not show up on infrared scanners.
 * Food:** The Polar bears favorite food is the blubber of a ringed seal (especially seal pups because they have a higher percentage of fat). They also eat walrus, whale, seals, fish, carcasses of stranded marine animals, and occasionally berries, grasses and kelp. The polar bears hunting style is designed to conserve energy, and they are stalk and ambush hunters. Often by just sitting and waiting by a seal hole for a seal to pop up. Then they'll use their huge paws to stun and kill, or kill with a bite to the head. They can eat 150-200 lbs. at one time, eating blubber and skin first, and then the meat. They need to average one seal every 4-5 days, and the minimum of one seal in 11 days will sustain them. Although they can eat birds, they don't usually do so, because it would take too much energy.
 * Economic Importance:** The principle use of polar bears in the circumpolar arctic is for subsistence purposes. These include consumption of meat; use of hides in the construction of clothing such as mittens, boots, fur ruffs for parkas, and fur pants; and small scale creation of items of handicraft.
 * Threats:** The Intergovernmental Panel on Climate Change and the Arctic Climate Impact Assessment have both predicted that the Arctic is extremely vulnerable to projected climate change. Polar bears will likely be shifted pole-ward if the sea ice retreats. According to new scenarios presented by the Nansen Environmental and Remote Sensing Centre and others, the polar ice cap will disappear almost entirely during summer in the next 100 years. The increasing changes in the sea ice that affect access to prey will have a harmful effect on the bears. With less food, polar bears will fail to reproduce more often and give birth to smaller young that have higher mortality rates.

Polar bears may be forced on shore for extended periods and rely on fat reserves left the previous spring for survival. In such a situation they will be more vulnerable to hunting if not regulated. If these periods become excessively long, mortality will increase. Sea ice is also used for access to den areas and if ice patterns change, existing den areas may be unreachable. Warmer temperatures and higher winds may reduce ice thickness and increase ice drift. Because polar bears must walk against the moving ice (like walking the wrong way on an escalator) increased ice movements will increase energy use and reduce growth and reproduction.

Polar bears are the apex predator and are exposed to high levels of pollutants that are magnified with each step higher in the food web. A key characteristic of the pollutants is that they tend to continue in the environment and don’t degrade. Many of the organochlorine pollutants are lipophilic or "fat loving" and bond tightly to fat molecules. Polar bears are mainly vulnerable to organochlorines because they eat a fat rich diet. Ringed, bearded, and harp seals comprise the main food of polar bears and the blubber layer is preferentially eaten by the bears and subsequently, the intake of pollutants is high.

Certain areas of the Arctic, such as northeastern Greenland, the Barents Sea and the Kara Sea, have higher levels of pollutants. Based on studies in other species, it is reasonable to believe that the pollutant load of polar bears in some areas are negatively affecting the immune system, hormone regulation, growth patterns, reproduction, and survival rates of polar bears. Recent studies have suggested that the immune system is weaker in polar bears with higher levels of PCBs. A main concern with polar bears has to deal with their reproductive system. There are suggestions that species with late implantation are more vulnerable to the effects of pollution through hormone disruption. Female polar bears are food deprived during gestation their pollution loads increase because as they use their fat stores, where pollutants are stored, for energy. Because the cubs are nursed on fat rich milk, the cubs are exposed to very high pollution loads from their mother.

Oil development in the Arctic poses a wide range of threats to polar bears ranging from oil spills to increased human-bear interactions. It is likely that an oil spill in sea ice habitat would result in oil being concentrated in leads and between ice floes resulting in both polar bears and their main prey (ringed and bearded seals) being directly exposed to oil. Another concern is that seals covered in oil may be a major source of oil to polar bears. Other studies suggest that polar bears are sensitive to disturbance at maternity den sites. Disturbance could occur both when a pregnant female is selecting a den site and during the winter-spring after the cubs are born. If exploration or development occurred sufficiently close to a den, the mother may abandon the den prematurely or abandon her offspring.

Over-harvest is an ongoing concern for some polar bear populations: particularly in areas where there is no information on population size and no quotas. It is important that population estimates and projections are based on validated scientific data. An additional concern is that population inventory programs occur rarely in some areas so if the harvest rate is above the sustainable level, the population may be reduced before the next inventory is made.
 * Conservation Efforts:**
 * || **THE INTERNATIONAL AGREEMENT ON CONSERVATION OF POLAR BEARS AND THEIR HABITAT, 1973** ||  ||
 * || 1. || This agreement states that the five polar bear nations (Canada, Greenland, Norway, the United States, and the former Soviet Union) shall protect polar bear habitat, especially denning areas, feeding areas, and migratory routes; ban hunting of bears from aircraft and large motorized boats; conduct and coordinate management and research efforts; and exchange research results and data. ||
 * 2. || The agreement allows the taking of polar bears for scientific purposes, for preventing serious disturbances in the management of other resources, for use by local people using traditional methods and exercising traditional rights, and for protection of life and property. ||
 * 3. || Each nation has voluntarily established its own regulations and conservation practices using the knowledge gained from the international community as a whole. ||  ||
 * || **UNITED STATES MARINE MAMMAL PROTECTION ACT, 1972** ||  ||
 * || 1. || Polar bears are protected under the U.S. Marine Mammal Protection Act (MMPA). ||
 * 2. || The primary objective of the MMPA is to maintain the health and stability of the marine ecosystem and to obtain and maintain an optimum sustainable population of marine mammals. ||
 * 3. || The MMPA prohibits taking and importing marine mammals unless a permit is issued for the purposes of public display, native subsistence, scientific research, or sustaining a depleted species. MMPA revisions in 1994 allow U.S. citizens to import polar bear "trophies" acquired in Canadian hunts. Polar bears in Alaska can be hunted only by Alaskan natives. ||  ||
 * || **THE ENDANGERED SPECIES ACT, 1973 (ESA)** ||  ||
 * || 1. || The Endangered Species Act of 1973 (ESA) is administered by the U.S. Departments of Interior and Commerce (the U.S. Fish and Wildlife Service and the U.S. Geological Survey). It seeks to stop the extinction of wild animals and plants in the United States, other nations, and at sea. ||
 * 2. || As of 2008, polar bears are listed as "threatened" on the U.S. Endangered Species List, mainly from the loss of important sea ice habitat. ||  ||
 * 3. || The MMPA prohibits taking and importing marine mammals unless a permit is issued for the purposes of public display, native subsistence, scientific research, or sustaining a depleted species. MMPA revisions in 1994 allow U.S. citizens to import polar bear "trophies" acquired in Canadian hunts. Polar bears in Alaska can be hunted only by Alaskan natives. ||  ||
 * || **THE ENDANGERED SPECIES ACT, 1973 (ESA)** ||  ||
 * || 1. || The Endangered Species Act of 1973 (ESA) is administered by the U.S. Departments of Interior and Commerce (the U.S. Fish and Wildlife Service and the U.S. Geological Survey). It seeks to stop the extinction of wild animals and plants in the United States, other nations, and at sea. ||
 * 2. || As of 2008, polar bears are listed as "threatened" on the U.S. Endangered Species List, mainly from the loss of important sea ice habitat. ||  ||
 * || 1. || The Endangered Species Act of 1973 (ESA) is administered by the U.S. Departments of Interior and Commerce (the U.S. Fish and Wildlife Service and the U.S. Geological Survey). It seeks to stop the extinction of wild animals and plants in the United States, other nations, and at sea. ||
 * 2. || As of 2008, polar bears are listed as "threatened" on the U.S. Endangered Species List, mainly from the loss of important sea ice habitat. ||  ||
 * 2. || As of 2008, polar bears are listed as "threatened" on the U.S. Endangered Species List, mainly from the loss of important sea ice habitat. ||  ||