Research Paper part 5: Fate forecast of the Sea Bear

Fate forecast of the Sea Bear

 

The sun shone brightly as it continued to rise in the cold spring morning. The ice flows drifted by slowly with the currents. Drops of salty water fell as the seals continued to play, gliding through the water like a bird flying in the air, swift and full of joy. As the day continues on, another decides to join in the harmonious gathering. Head held high, the majestic polar bear appears. As he approaches, all others scatter for they know the real beast hidden behind the welcoming disguise. These mighty mammals have lived in the arctic along with their only enemy, humans, for ages. They have had none else to worry about until the changing climate started melting the ice environment they need for survival. The native group of the North Slope, known as the Inuit, say polar bears will do fine with all the changes. However, scientists have stepped in with their studies saying that polar bears are facing a dilemma that may wipe them out entirely. Although Alaskan Natives disagree with it, the polar bear should remain on the endangered species list because their changing environment negatively influences their hunting, energy, and reproduction.

Polar bears are very unique creatures to both the animal kingdom and their bear family. They live in the Arctic Circle area of the world. The polar bear’s Latin name, Ursus Maritimus, means sea bear, which corresponds well with them because they spend so much time out in the ocean or the ice above it (Animals and Pets—National Geographic Kids). Polar bears swim very well and very fast with the help of their large paws. According to “National Geographic” (n.d.), males normally weigh in a range of 720-1700 pounds, while females, being smaller, range from 500-600 pounds. They can grow to be as tall as ten feet high when standing and have a rough skin surface on their paws to keep from slipping while walking on ice. These creatures are masters of surprise attacks. They are able to walk as quietly as the falling snow on a calm day and use a method called stalking when hunting their prey (A. Brower, personal communication, fall 2007). Their white fur helps them stay camouflaged while hunting. The hair strands are hollow, which allows their fur to appear white because it the air within them scatters light that hits (Everyday Mysteries, 2010). Underneath the thick coat of fur is black skin that allows them to keep warm by absorbing the heat from sunlight (the hollow fur may also contribute to this because it lets the sunlight reach the skin instead of blocking it out). Their diet consists of a number of different meats including walrus, fish, beluga whale, bowhead whale, bearded seal, ringed seal, as well as a few others. Most polar bears are “left handed,” meaning that they use their left paw to strike and kill their prey (Animals and Pets – National Geographic Kids).

Climate change is the result of something called the greenhouse effect. Lee, Lester, Lambert, and Jean-Baptiste (2007) define the greenhouse effect as the warming of the Earth’s atmosphere from captured chemical compounds, such as methane and carbon dioxide, etc., that pose as greenhouse gases and hold in the radiation that usually passes through the atmosphere (p. 117). It is something that happens naturally. However, this effect has been increased through human activity and furthermore caused the earth to warm more rapidly. Factories, cattle farms, landfills, and other things that emit water vapor, carbon dioxide, methane, nitrous oxide, and chlorofluorocarbon gases are all human-based causes for the intensified greenhouse effect (Lee et al., 2007). Unfortunately, the rapid warming from these amplified effects is taking a toll on the arctic environment

The arctic environment is a home to many species of animals including the polar bear, but as the temperature rises; the environment transforms to meet the new climate conditions. Prowse, Furgal, Wrona, and Reist (2009) report “As the climate continues to change, there will be consequences for biodiversity shifts and for the ranges and distribution of many species with resulting affects of availability and quality of resources…” (p. 282). One can see that Prowse has just described what is going on in the arctic now. It is well known that the effects of climate change are seen more prominently in the arctic. This is because the arctic is a rather cold place, containing ice in much of the territory, and warmer temperatures would obviously have an affect on ice. Studies have shown that the sea ice extent has been decreasing at an amount of about nine percent per decade (Derocher, Lunn, Stirling, 2004. p.164). That may seem like a small amount, but as time continues, it adds up and may disappear sooner than expected. Especially if the temperature rises more than it already has. It is true that more ice is formed over winter. According to Scheirmeier (2008), a great deal of the ice seen out in the Arctic Ocean is newer, or first year ice (266). Although it sounds like a good thing, it poses as more of a threat than an advantage because first year ice is not strong. New ice melts easier due to its weaker and thinner characteristics while aged ice is able to last as a result of piling up and strengthening throughout a number of years (Scheirmeier, 2008). Since the new ice melts so effortlessly, it leaves the aged ice for polar bears to depend on.

Polar bears need the ice in order to hunt. As mentioned earlier, polar bears hunt seals. The ringed seal is their main prey with the occasional bearded seal. Ringed seals live with the ice. Wherever the ice goes, seals follow. In order for polar bears to get to their prey, they must swim long distances during the summer months. The trip may be perilous to some because the ice flow is smaller and now farther from land. In January of this year (2011), Los Angeles Times’ Kim Murphy reported on a female polar bear that was forced to swim about 426 miles from shore just to reach an ice floe. She started off with a cub, but sadly the cub was not strong enough to make it the whole way. This was merely one report on one polar bear and her cub. There are probably many others that have attempted the exhausting swim to the pack ice and failed. However, Native Alaskans believe

Continuing on, ice is a necessary element for polar bears while hunting because it helps them stay camouflage and it assists with their hunting techniques. Having transparent fur, these creatures count on light to make their fur appear white and thus camouflage themselves with the surrounding ice and snow.  The ability to be camouflage is especially helpful when polar bears wait near a seal’s breathing hole and while using their stalking hunting method. When the ice is too far to reach or not available, polar bears are forced to hunt from land or while swimming. Catching prey is much more difficult when the predator can be seen from a ways back. It gives the seals time to hide or swim away and makes the bears work harder to get a successful catch. Harder work means more energy is used and needed to keep these bears going.

Energy becomes an increasing problem as climate change continues. Not only does climate change weaken the ice, but it also causes the spring break up to occur in earlier months than it normally used to. Engelhaupt (2009) explains, “In spring, the Arctic sea ice begins to melt and break apart. Over the past 25 years, the timing of this melting has become less predictable as a consequence of warming in the Arctic, varying by more than a month.” That time of the year is very important for polar bears because they are storing energy and getting ready for the summer months. Summer is a time of fasting for polar bears. They journey throughout the land and water, but they do not eat much. Springtime is also the preferred time of year to hunt seals because mothers and cubs have then recently emerged from their dens and their long sleep and need to eat. Derocher (2004) reported that since break up is occurring earlier, polar bears do not have the time necessary for consuming a decent amount of food to have enough energy to make it throughout the summer. It is important for them to eat as much as possible before summer begins because during that time, they mostly rely on their stored fat as a source of energy, rather than eating.

Furthermore, the amount of energy needed to survive the summer has grown because of the shrinking ice. During this time, a polar bear’s body “recycles urea and keeps creatine levels up, which means they use up their fat and conserve protein” (Gillis, 1991). Since the shrunken ice is much smaller than it used to be, the extra amount of energy required to swim is drained much quicker than it should be. Even so, polar bears still insist on embarking on the long journey. They love their ice so much they would die in the attempt to reach it. In Barrow this year, we had several polar bears arrive to shore. As soon as they landed they plopped down on the beach and slept. We could tell they were so exhausted by the way they acted when we tried to scare them down the beach, which was done so they would not be within the town area. It was as if they did not even care that we were near them. The Department of Wildlife Management bear watchmen stood nearby with guns and town residents drove by with all-terrain vehicles, which usually spooks bears enough to run the other way. That is how tired they were.

The trouble continues when the depleted ice affects polar bear reproduction, causing their population to decrease. Like most other animals, it is important for a pregnant female to consume larger amounts of food to have enough nutrients and energy to continue the pregnancy. As mentioned before, the shrinking ice causes problems for hunting bears. Like a chain reaction, the dwindling amount of food consumed affects the energy and nutrient intake of the polar bear to result in a miscarriage. “Hunting troubles along with the substantial changing of the environment creates stress for polar bears and may cause reproduction complications,” as Courtland (2008) explained in her article.  It not only affects the reproduction rate, but also how long it takes for a cub to wean off the mother’s milk. “Female polar bears normally keep offspring for 2.5 years and therefore, given that the cubs survive until weaning, breed every three years” (Derocher, 2010. p. 940). So females should usually breed every three years after their cubs have weaned off milk and have learned to hunt on their own.

During the winter, pregnant female polar bears dig dens within the ice or snowdrifts where they sleep until spring arrives. It is during this sleep that they give birth to their cubs, who stay in the den until it is time for the mother to climb out and start hunting for food (Armstrup, McDonald, Nielson, & Simac, 2004). Once they emerge from the den, the mother takes her cubs and searches for food. She must eat enough to produce a great amount of milk to feed her cub, while at the same time keeping herself healthy through the summer. Since spring has been occurring earlier than normal, it allows warmer temperatures to cause collapsing dens. In 1989 a female polar bear and her two newborn cubs were found dead because the den had collapsed (Clarkson and Irish, 1991). If they were able to collapse twenty years ago when the climate was not as warm, dens may be weakened easier today.

Even after all this, the native people of Alaska still disagree with listing the polar bear as an endangered species. They believe that polar bears are live and well, saying that polar bear population numbers are higher than ever and that because they do not see any bears with malnutrition there must not be any (Howe, 2010). It may not be apparent to them, but what they see can be an illusion, in that the abundance of polar bears they are seeing is from bears coming to land as a result of the lack of ice they are able to land on. The article “Polar bear listing to affect ANWR and Alaskan arctic” (n.d.) says “…the Arctic Native population does not support listing due to perceived inaccurate science…, threats to cultural ways of life, and lack of consultation in the decision making process…”  They say it threatens the cultural way of life because listing the polar bear would prohibit the hunting of them as well. On the other hand, it would protect them from being overhunted. The prevention of hunting may be one of the main reasons they do not like the idea of being listed on the endangered species list.

As I have pointed out, the shrinking ice has become a big problem for polar bears. As it shrinks, the polar bear’s hunting becomes more difficult and results in a decrease of food consumed, which sets off a kind of chain reaction that in turn affects their energy levels and on to reproduction. Since such changes are endangering the polar bear population, they should be kept on the endangered species list. As for the native Alaskans, the best thing to do in order to have the best of both worlds may be to allow hunting of polar bears but with a quota. That way, overhunting would not take place and there would still be enough polar bears to keep their population somewhat stable. Also, maybe they can request to be included in the decision making process and use their passed down knowledge of polar bears combined with scientific knowledge to come to a conclusion. It is a decent compromise to think about.

 

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