Polar Bear Report Essay, Research Paper
Polar Bear ( Thalarctos Maritimus )
After draging behind the Female Polar Bear for approximately two months the male Polar Bear so mates with the female Bear. Females are induced ovulators, which means the act of copulating causes a female to let go of an egg for fertilisation ( polar bears alive ) . Fertilization takes topographic point internally. Several yearss of copulating interactions may be required to excite ovulation and warrant fertilisation of the egg. In making so it starts the gestation period.
The entire gestation period is about eight months. During gestation the fertilized egg divides into a hollow ball of cells one bed midst, so the ball stops turning and prevarications free drifting in the womb for about four months. The cells so implant in the uterine wall and go on to develop ( Sea World ) . Delayed nidation assures that the greenhorn is born during the best clip of the twelvemonth for endurance and allows the female to acquire into good physical status and uses her energy for nursing her new born greenhorn ( Sea World ) . The existent embryonic development is estimated to be four months ( Smithsonian Institution ) .
Most grownup females give birth one time every three old ages. Sea World states, that at birth polar bear greenhorns weigh about 454 to 680g and are about 30cm long, nevertheless, Bears Den states that at birth the immature weigh about 450g. The pelt is all right at birth, doing the cubs expression hairless ( Sea World ) .
Female polar bears go through a period called Denning when they are pregnant, in which they begin lodging fat. They need to derive at least 441 lbs while pregnant. ( World book encyclopaedia ) . Normally they dig lairs in snowdrifts on southern confronting inclines. Some excavation earthen dens that subsequently become covered by snow. Most lairs are on land within 10 stat mis of the seashore. In some countries lairs are more than 62 stat mis from the seashore. Lairs can average to about 1,800ft above sea degree ( National Geographic ) . The Den is used for nursing the babes in the cold air temperatures. Because of organic structure heat and snow insularity, the lair stays warmer than the outside temperature.
Cubs stay with their female parents for about 2 old ages, although some may be weaned at 1.3 old ages and others stay every bit long as 3.3 old ages ( Sea World ) . They open their eyes within the first month and in approximately two months they begin walking. By this clip they have thick, milky pelt and their dentitions have about wholly grown in.
In about March or April the female parent and cubs come out from the lair, the greenhorn now weighing 20-40 lbs. The female parent and greenhorn remain around the lair for approximately 12 more yearss ( Sea universe ) . The greenhorn so get down eating solid nutrient when the female parent makes the first putting to death on the sea. The greenhorn grow rapidly on their female parent s fat rich milk and seal blubber. By eight months of age, they weigh over 99 lbs ( national geographic ) .
Polar bear greenhorn learn to run by watching their female parent. Cubs will seek runing in their first twelvemonth ( Bears Den ) . When they are about 30 months old, a female polar bear is ready to engender once more and a grownup male may get down following her ( Sea World ) .
Female Polar Bears reach sexual adulthood at about 4 old ages old. Male Bears reach their sexual adulthood at 6 old ages old ( Bear Den ) . However, most male Polar Bears Don T mate until 8 to 10 old ages and older. They grow two to three times the size of female polar bears ( World Book ) . Sea World states that Boars ( another name for Male polar bears ) weigh between 772-1,433 lbs and can acquire to about 8-10ft long. Sows ( another name for female Polar Bear ) weigh about 331-551 lbs and are 6-9ft long. Bears Den states that a adult Polar bear may be every bit much as 9.5ft long and weigh about 1,000 lbs, with an extreme of 1,600 lbs.
Compared to other bears, Polar Bears have elongated organic structures and long slender cervixs. They can change from pure white to light brown pelt, depending upon the season, angle of visible radiation, and populating environment.
Aggression occurs between males during the genteelness season. Before a Polar Bear gets to copulate with the female it must contend against the other male Polar Bears to find whose traveling to copulate with her. Aggression besides occurs when males attempt to steal nutrient from another household of Polar Bears. If they are caught there can be many conflicts between them. Worlds may meet polar bears wherever human and polar bear home grounds overlap. Polar bear onslaughts occ
ur most frequently at sites of human habitation, such as runing cantonments, conditions Stationss, and towns. Compared to other bears, polar bears are more willing to see worlds as quarry. ( Polar bears alive ) . Adult polar bears have no natural marauders. Males on occasion kill other males viing for couples. Males sporadically kill females protecting greenhorn. Cubs less than one twelvemonth old sometimes are prey to adult male polar bears and other carnivores, such as wolves. Malnourished female parents may cannibalise newborn greenhorns ( Sea World ) .
Polar Bears coupling takes topographic point in April and May. They don t alteration colour nor do any dances as a consequence of coupling. Male polar bears have been seen following the paths of engendering female polar bears for more than 62 myocardial infarctions. Scientists are unsure what signals males use to track genteelness females ( Smithsonian Institute ) . Females are attracted to Males by the aggressive behaviour they have during engendering season. The toughest male out of the battling males is the Bear the female is attracted to the most after conflict ( World Book ) .
A polar Bears tummy can keep an estimated 15 % to 20 % of its organic structure weight. It can digest 84 % of the protein and 97 % of the fats it eats ( Sea World ) . They chiefly eat seals. A seal weighing 121 lbs could supply up to eight yearss of energy for a Polar Bear ( Bears Den ) . They use a method called still runing, in which they remain inactive beside a eupneic hole waiting for a seal to surface. The Polar Bear so bites onto the caput or upper organic structure and so flips it onto the ice. They besides stalk nutrient on land and in H2O. These methods are called aquatic chaff and land chaff. Once a seal is captured the Polar Bear bites the seals head several times before dragging it from the H2O to feed. They eat the tegument and fat foremost followed by the meat. They so leave the staying carcase on the ice for it to decompose or for another animate being to banquet.
Polar Bears Don T have many diseases ; nevertheless, I found a few diseases that Polar Bears can acquire. One of them is Parasitic Worm Trichinella. The unwellness begins when the infective cysts are eaten with the flesh of any flesh-eating animate being. The cysts are digested and so released and the Larvae so invade the little bowel. The female so hatches larvae that are carried by the blood and lymph to the musculuss. The undermentioned can go on during the procedure, diarrhoea, sickness, abdominal spasms, febrility, musculus hurting, and swelling.
Polar Bears can populate 20 to 30 old ages, but merely a little proportion of Polar Bears live by 15 to 18 old ages.
Starvation is the greatest menace to Polar Bears. Many times larger Polar Bears trail away the older Polar Bears. In making so, the older Polar bears starve to decease. If a polar bear gets ill they may non be able provender themselves and many times they die.
Environmental menaces are a immense menace to Polar bears besides. Oil spills and Toxic waste causes a menace to many of them. Human-made toxic chemicals such as polychlorinated biphenyl s ( PEB S ) , DDT ( DDT ) , and Chlordane s ( Sea World ) .
Some Polar Bears dice during the Hunt of nutrient or combat during the genteelness period.
Their organic structure temperature, which is usually 37C ( 98.6F ) , is maintained through a thick bed of pelt, a tough fell, and an insulating bed of blubber. This first-class insularity keeps a polar bear warm even when air temperatures bead to -37C ( -34F ) . Polar bears normally swim under H2O at deepnesss of merely about 9.8-14.8 foot. They can stay submersed for every bit long as two proceedingss ( Sea World ) .
1. The Oldest known Polar Bear in the Arctic lived 32 old ages ( Bears Den )
2. The Oldest known Polar Bear in a zoological park lived 41 old ages ( Sea World )
3. The largest Polar Bear of all time recorded was a male weighing 2,209 lbs, it was 12ft long ( Bears Den )
1. Sea World, Inc. 1997
hypertext transfer protocol: //www.seaworld.org/polar_bears/pbindex.html
2. Smithsonian Institution 1997
hypertext transfer protocol: //www.mnh.si.edu/artic/html/polar_bear.html
3. The Bear Den
hypertext transfer protocol: //www.nature-net.com/bears/polar.html
4. Polar Bears Alive
hypertext transfer protocol: //www.polarbearsalive.com
5. National Geographic January 1998 issue
6. World Book Encyclopedia 1990
Chicago World Book-Childcraft international, Inc