Polar bears have usually been found to mate between April and May. Soon after fertilization, the embryo of the polar bear stops developing and floats inside the mother’s womb for four or more months. This process, called delayed implantation, allows the mother to feed and build up enough body fat to survive eight months of hibernation. Females mate every other year, and cubs are born about every three years, generally in litters of two, but more and more cubs are dying because they cannot survive their first year. At birth, the cubs weigh approximately one and a half pounds.
Their diets consist of mainly seal that they hunt or other close by animals, such as fish, seabirds, arctic hare’s, reindeer and musk oxen. A large fully grown adult male weighs around 350-680 kg, while a smaller fully grown female is about half that size. The polar bear is a species of bear closely related to the brown bear, but evolution has changed certain characteristics so it can fit the ‘narrow ecological niche’ that it lives in. Its main body features are adapted for the freezing cold temperatures, moving across the cold, snowy and icy landscape, for swimming in open water and hunting.
The World Conservation Union’s Polar Bear Specialist Group has stated that polar bear populations could drop more than 30 percent in the coming 45 years. Canada and the USA have classified the polar bear as a species of animal requiring special protections. The HSUS believes all nonessential human exploitation of polar bears, such as capture for display or trophy hunting, should be prohibited, this includes hunting and bear baiting.
Polar bears are the top predators in their natural arctic habitat and have evolved uniquely to settle into this landscape. They face growing threats to their lives from habitat loss and starvation, specifically from:
-Climate change and sea ice reduction
-environmental contaminants and chemical pollutants
-hunting and capture for public display
The habitat loss is in large part a climate change driven issue alone, even though pollution has impacted polar bears habitat. It’s also had a huge impact on them due to their specialized diet. They are the top predator of their region, so this exposure has been more along the lines of toxins through their food sources. Polar bears are dying out mainly because their homes are melting. This is due to an atmospheric procedure called ‘The green house effect.’ It traps heat in, and ‘warms the globe, effecting climate on the earth.’
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The main problem biologists are having with polar bears is that unlike most large carnivorous animals, they are not territorial. Most bears hunt in an area that they protect, and stay in small hunting groups whereas the polar bear is a free ranging species and therefore does not stay in the same place. This makes the preservation of their habitat extremely important for scientists. Since they move over great distances, following the ice flows for access to more land and main food sources, they are able to reach the ‘Denning areas’ where they are able to breed, and because the things they need are so vastly spread, there is very little that can be done for the species.
One possible idea that scientists have had is to track specific bear’s around 3 separate areas. The WWF have done this with a specially designed system called the WWF Cannon polar bear tracker. This tracker allows researchers to see the paths of certain polar bears around the area, and this therefore make them easier to find if needed for more research, and even help by the means of preventing them from entering human territory, or staying away from broken off ice shelves to prevent drowning. The three areas that bears are tracked in are;
The South Beaufort Sea, USGS Alaska Science Center (University of Alberta) – 6 bears
Hudson Bay, Canada – 6 bears
Svalbard, Norwegian Polar Institute – 4 bears
These bears are all tracked via a tracking collar. These collars send GPS signals to a satellite, and then back down to a computer in the WWF institute. Researchers use this information to see where polar bears and most likely to be found, where they mate, hunt for food, and to see where their denning areas are. This will enable WWF to do something about the dangers they are faced with. They can, for instance try and keep bears away from shipping lanes as a lot of huge ships pass by the areas like Hudson Bay.
Positives of tracking bears
Negatives against tracking bears
– Polar bears are able to be seen wherever they go, and this enables scientists to follow their main routes to important resources. It also gives them and insight to the distances polar bears are able to move, and this includes where they can no longer go because of ice shortage.
– Although this system allows scientists to see where the polar bears go, it doesn’t necessarily help the bears. They are unable to be controlled by the collar, and they are also unable to know if a bear has died or has got rid of the collar.
– another negative point is that not all bears are able to have tracking collars fitted, so only a few are actually being followed, this doesn’t show the majority and where the go.
As a top predator, polar bears are exposed to relatively high levels of pollutants through their food. Constant natural pollutants (Pops) range widely and include poisonous substances such as heat resistant chemicals (PCBs), industrial waste products such as dioxins and furans; and fertilizers and pesticides like DDT, dihedron and linden. Polar bears that have higher levels of some POPs have lower levels of vitamin A, thyroid hormones, and some antibodies. These are all important in the growth, reproduction and the ability to fight off disease stages of a bear’s life. These chemicals are putting the bears in danger of bone mineral density loss, hormonal imbalance, physiological damage, and compromised immune systems. Bone mineral density loss is especially bad if it is found in female polar bears, which must have large amounts of phosphate and calcium during the birth, pregnancy and nursing stages of having a cub.
Some of these chemicals are not used anymore but they stay in the environment for many years after they have been put into the system. The most likely root for how the chemicals got to the arctic in the first place is that chemicals were transported from the south by wind and warm water currents. They then hit the colder arctic; the chemicals are deposited on the water, on the sea bed and in the ice. This then enables the chemicals to enter the food chain. As larger animals eat smaller ones, the chemicals become more concentrated, so that the largest animals of all often have the highest load of chemicals in their bodily systems, putting them in more danger.
This is another aim of the WWF, to eliminate chemical infection to the arctic. This may be close to impossible to stop it all together, but the aim that they are trying to achieve is to educate people on how to dispose of waste appropriately and not in water.
Breeding programs are not a solution, but a temporary answer. Sea world in the USA has a lot of polar bears that have been put in captivity, and that were bred there. Polar bear numbers are known to be relatively low, and in some places are getting better. At the moment they are a stable species, but this could change in the near future. With the current threats of global warming, the bears are experiencing shorter winters are having a shorter time to eat seals to bulk up for the summer. As well as this, results that have been gathered from recent research show low cub survival rates. Polar bears are kept in captivity as a possibility to maintain these numbers and also educate the public about the Polar bears lifestyle and habitat, and how things they do can affect them.
Sea world and the WWF use established USA & International breeding programs, which use proven scientific models and research. Blood lines are always monitored to so that the institutes can determine who is able to be bred. Breeding is often controlled by separation, which means putting two polar bears together, and sometimes bears are transported over seas.
Pregnant female polar bears need a quiet environment where they feel safe and comfortable and are able to raise her cubs. Some institutes offer a ‘maternity’ den in which pregnant female bears are put in. This den has often has thicker walls that can also be soundproofed if needed to reduce noise and is monitored by CCTV Camera’s. The den is usually fully equipped with the materials needed to make a warm nest for the cubs. When breeding any animal, blood lines must be closely monitored to ensure that cross breeding does not occur.
POSITIVES OF BREEDING
NEGATIVES OF BREEDING
Polar bear numbers are able to be increased.
Bears are able to be studied, so we are able to find out more about them.
The bears are able to be used to educate the public on what’s happening to their landscape.
There are no immediate threats while they are being cared for.
Bears will most likely be unable to be released back into the wild because they will not be able to survive.
Bears will never have the real life that they would have if they were in the wild.
Polar bears will inevitably be in danger or even extinct in the next century, because climate change cannot be stopped. It can be reduced though, and the only way to reduce this relies on the education of others, otherwise we could be faced with a modern dilemma of never seeing some of the most beautiful species of animal ever again. But will breeding programmes ever be enough for polar bears? Or is their future bleak and already visible? The answer relies with us, the public, humans – the ones who make the planet worse everyday.
Polar bears do not deserve to suffer for things we are doing to them. They can’t speak, they can’t let us know if something’s wrong, so we have to know – and we have to therefore fix it. It’s simple enough, people survived thousands of years ago without power, without vehicles, oil, plastics, so why do we need to change now, and harm the world we live in.