Polar Bears Are Losing Their Homes
Polar Bear Features
Polar bears are the largest land carnivore on Earth and when standing on it’s hind legs, can reach 12 feet tall. These bears can grow up to 10 feet in length and weigh up to 1,700 pounds. The polar bears fur is thick and creates an oil that can repel moisture to be able to easily shake off water so it won’t freeze when it’s out of the water. They also have 4 inches of fat under the thick fur that helps to keep it warm in the sub-zero temperatures of the arctic waters.
Polar bear feet are also a unique and useful tool in surviving in such an icy cold climate. Their large paws and claws are like snow tires and help the animal to cling to snow and ice. Polar bears are able to run up to 25 mph when needed. They have twelve inch wide paws that help spread out the bears weight and keep it from sinking into the snow. Their large paws are also slightly webbed that help them when swimming. Polar bears can swim for more than 60 miles at a time.
Polar bears live in an area called the Arctic ring of life. This area consists of the Arctic inter-island archipelagos and the waters surrounding it and all over the continental shelf. Polar bears like the areas where the sea ice meets water like polynyas and leads, as it allows them to easily hunt seals. Freshwater in these areas are usually locked up in snow or saline, but polar bears can produce water through their metabolism of the fat and blubber found in seals. Polar bears are found mostly along the polar ice pack and not the polar basin that is close to the north Pole. This is because the area is harsh for seals and so they wouldn't be able to hunt as much as they would need.
As the ice and watery areas appear and disappear through the year with weather changes, the seals will migrate in response to these changes. The seals are a main food source for the bears so they must follow their prey where it goes, so because of this polar bears have been found in more human populated areas such as the Hudson Bay, James Bay and other places. When the ice melts completely in the summer, some polar bears are forced to go onto land and wait for months until the water freezes up again.
Because of climate change and global warming the polar bears habitats are slowly dissolving and not coming back. This means the bears are being forced to move into other areas that can be dangerous to humans and will cause conflict with other types of animals. Polar bears are beginning to starve and mothers have now been seen abandoning their cubs because they simply can’t feed them or their cubs are born too weak.
Diet and Hunting
Polar bears are carnivores by nature and their diet mainly consists of seals, walruses, fish, caribou and even beached whales. They can and will eat many other items including some fruits and vegetables. Seals are their main source and they have a very unique hunting technique that they use. Polar bears will find a hole in the ice that seals will use to breach and breath when they are out swimming. The bears will find these breathing holes and will use their massive white paws to cover their black noses to hide. They sit and wait until a seal pops it’s head out of the hole to breath and with a swipe of it’s large paw it hits the seal on it’s head and using it’s massive canine teeth it grabs the seal and drags it out of it’s hole. The polar bear will use it’s sharp incisors to tear through the seals flesh and blubber as it eats.
Mother polar bears will sniff out baby seals and crash through the snowdrifts and into the seals birthing lairs. Baby seals are very fat and baby polar bears need a high fat diet.
Polar bears will also scavenge for food and are quick to feed off of beached whales or other dead animals found in the snow. They will even eat other polar bears if found dead. A pack of polar bears have been known to take down an adult walrus.
Polar bears can eat about 15% to 20% of it’s body weight in a single day, and generally eats this much when it’s energy demands are high. This could be when a female is pregnant or just gave birth. These bears need to eat at least 5 pounds of fat per day to obtain enough energy to survive.
Did You Know?
A Polar bear can detect a seal resting on the ice from 20 miles away thanks to it’s incredible sense of smell.
Polar bears are mature and ready to breed at 4 to 5 years old while males don’t reach sexual maturity until 6 years old. Due to the competition for females, some males don’t mate until they are 8 or 10 years of age. These bears can live up to 30 years old so they still have time to produce cubs. Polar bears mating takes place in April and May on the sea ice in the best sea hunting areas. Males have been known to follow a breeding female for up to 60 miles and will engage in intense fights with other males in the area. Males will get into violent fights that usually leave scars or broken teeth, just for a chance to mate with the female in the area. The male and female will stay together and mate repeatedly for a full week. Once the females eggs are fertilized, they will remain in a suspended state until August or September. Because of this, it is possible that a females cubs of the same litter could have different fathers. During the four months that her fertilized eggs are suspended, the female will eat large amounts of food gaining at the very least 440 pounds and often end up doubling her body weight.
At the end of fall, when ice floes are at their lowest and hunting becomes more difficult if not impossible, the female will dig a maternity den in the snow. The den consists of a narrow entrance tunnel leading to three different chambers. Some polar bears in a sub population will reuse the same den area each year. The mother polar bear will enter a sort of hibernation, or a dormant state. She does not contentiously sleep however, her heart rate will slow from 46 beats to 27 beats per minute. Her body temperature doesn't decrease either as it would with other hibernating mammals.
The female polar bear gives birth between November and February and her cubs are born blind and with light brown fur. They typically weight less than 2 pounds also. In captivity, polar bears have been known to give birth in the early months. The earliest recorded polar bear birth was on October 11, 2011 in the Toronto zoo. The average number of cubs born is two but three have been seen before as well as just one. The family remains in the den until mid February or mid April. The mother nurses her cubs with fat-rich milk while maintaining her fasting.
By the time the mother exits the den her cubs should weigh about 22 to 33 pounds and for the first 12 to 15 days the family spends time outside but stays close to the den. The mother lets the cubs learn to walk and play and she will graze on vegetation or whatever else she can find close to the den. Once the cubs are able to walk and run, the family starts it’s long walk to the sea ice so the mother can hunt seals again and teach her young how to do the same. The cubs will imitate their mother’s hunting methods and learn how to survive on their own in the future.
Mother polar bears are known for their affection and love towards their cubs and also for their fierce protective nature of them. Female polar bears have been noted in the wild of adopting orphaned cubs. Sadly, the opposite has also been seen where adult polar bears of either gender have been seen killing and eating lone cubs but this is very rare for females. Mother bears have even gone head to head with adult male polar bears when they get too close to her cubs.
Polar bear cubs are typically weaned and able to go off on their own at about 2 1/2 years but lately 42% of mothers are leaving their cubs at just one year old. The mother will chase them away or simply abandon them when they are old enough to fend for themselves. Siblings tend to stick together and hunt together for a few months before parting ways.
Did You Know?
Some polar bear mothers can fast up to 8 months while pregnant and weaning her cubs.
Polar bears are not like other bears, they aren't territorial. Their reputation is a voraciously aggressive animal but in truth they are cautious and don’t like confrontation. Most of the time they decide to run or escape rather then fight. Polar bears that feed regularly and aren't looking for a meal rarely attack humans unless they are severely provoked. Polar bears don’t have much interaction with humans so a hungry polar bear looking for a meal can be unpredictable and tend to act fearless towards humans. They have been known to kill and even eat humans at times though it is still rare. Once instance happened with a Japanese wildlife photographer who was pursued by a very hungry male polar bear. This was in northern Alaska. The bear started running at the man but he luckily made it to his truck, however the bear reached the truck and tore off one of the doors before the photographer was able to drive away.
While polar bears do live solitary lives, they often play together for hours at a time and have even been observed sleeping in an embrace. Nikita Ovsianikov, a polar bear zoologist, described male polar bears as having “Well-developed friendships”. Cubs are especially playful and will play fight often. Play fighting is essential in learning good skills for later more serious combat during mating season.
Polar bears are also mostly a quiet animal but can be vocal when needed. These bears communicate with various sounds and vocalizations. Mother bears will communicate with their cubs through moans, chuffs and have been observed humming while nursing. Cubs and sub-adults distress calls are consist of bleats. Nervous polar bears will make noises such as huffs, chuffs and snorts and an aggressive polar bear will hiss, growl and roar.
An interesting event happened in 1992 when a photographer near Churchill took photos of a polar bear playing with a Canadian Eskimo Dog. This dog was one tenth of the size of the bear and they would wrestle harmlessly together every afternoon for 10 days in a row. Researchers have no idea why or how this pair became friends, perhaps the polar bear though if it demonstrated it’s friendliness the dog would share it’s food. This sort of friendly socialization is incredibly uncommon as polar bears are typically very aggressive towards dogs.
Conservation And Threats
Polar bears population sizes are hard to estimate as they occupy remote home ranges and fieldwork for researchers is hazardous. It is estimated by the International Union for Conservation of Nature (IUCN) that in 2015 the polar bear population was around 22,000 to 31,000 but the current population trend is unknown. Even with these numbers, polar bears are listed as a vulnerable species. It is expected that the population will decline at over 30% over the next three generations. This is due to climate change, pollution from toxic contaminants, conflicts with shipping, oil and gas exploration and drilling and human-bear interactions from harvesting and recreational polar bear watching.
Climate change/ Global warming is a huge factor as it is causing malnutrition and starvation due to habitat loss. With the raise in temperatures, the ice is melting faster then normal and polar bears use ice to hunt for seals. It’s said the ice is beginning to break up three weeks early. So if they can’t get on the ice to hunt for seals then the bears cant’ eat. Bears who are force to forgo food for longer periods of time often are pushed to the shore well before they are able to build a sufficient fat reserve to help them survive without food. With less ice, the bears are also being forced to swim longer distances and further deplete their energy stores and can lead to them drowning.
Less food means lower reproductive rates and less healthy cubs and mothers. Survival rates for cubs will drop and it can lead to poor body conditions in bears of all ages.
With the melting ice and less food available, polar bears have started to forage close to humans. They have been found digging through dumps for scraps of food and it’s getting more prevalent. Increases in bear and human interaction will lead to more hungry bear attacks.
Pollution is another issue polar bears are facing. These bears accumulate high levels of persistent organic pollutants like polychlorinated biphenyl (PCB’s) and chlorinated pesticides. Halocarbons concentrate in fat and blubber and with the polar bears diet consisting of very high fat and blubber, their bodies are the most contaminated of Arctic mammals. Halocarbons mimic hormone chemistry and biomarkers such as immunoglobulin G and retinol so they are known to be highly toxic to other animals. PCBs are studied the most and have been known to be associated with birth defects and immune system deficiency.
These chemicals have been banned internationally after they realized the harm they do to the environment. Even after it was banned, it was still rising in polar bear tissue due to the chemicals being spread through the food chain however the tissue concentrations have been slowly declining since 1989.
Oil and gas development is another thing causing problems for polar bears. Oil spills in the Arctic would most likely pool and concentrate in the same area that the polar bears and the seals concentrate. Oil spills can cause hypothermia in polar bears if they get it in their thick fur. The fur helps protect the bear by providing insulation and being water resistant, but if it’s covered in oil it can’t do it’s job. If the bears try to lick the oil off their fur to clean themselves it will lead to fatal kidney failure.
Oil exploration can disturb mothers in their dens as well and these areas are sensitive to the bears. A major disturbance to the den can cause the mother to abandon her cubs or the den prematurely.
Scientist believe that by 2050 we could lose over two-thirds of the polar bear population. If we take the lowest estimate of what the population is said to be now, that would mean we would lose up to 15,000 polar bears by 2050. Most people today don’t feel that polar bears need to be protected as the population has increased over the last 50 years and the population has been relatively stable. The past populations were reported by stories from hunters and explorers and not based on scientific research so we can’t determine just how truthful or factual the population numbers in the past were. Also, in the later years there was a cap and regulation changes put in place for harvesting that allowed the over hunted species to recover. That being said, with the recent effects of climate change among other factors, the changing and melting sea ice is effecting polar bears hunting and feeding behavior.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.