After spending what we thought was an unstoppable day on the tundra viewing a mother polar bear and her two cubs, the next day proved us wrong. This time we again saw a polar bear off in the distance of our lodge early in the morning. This bear had no interest in coming any closer, which was perfectly fine with us. Taking in the beautiful colors of the sunrise as we headed out on the Tundra Buggy for the day was enough. However, we were in for quite a surprise!
A bit into our trip, we encountered our mother polar bear and her cubs, so we decided to stop for awhile and see what would happen. Another Tundra Buggy with guests had also stopped, and the bear family had some interest in them. We watched in amazement as the bears slowly inched their way toward them, seemingly headed by one brave cub. The mama was relaxed and allowed her baby to approach the buggy, sniff the tires, stand up to get a better look at the people, and then go back to Mom and sibling to roll around in the scrub brush. A little time later, we got our turn! This time, both cubs decided we were interesting enough to explore and came over to us. NOTHING can describe how I felt looking into a young polar bear cub’s eyes: dark pools of curiosity, completely unaware of the human impact on his simple, yet complex environment. Soon after, mama bear settled down and nursed her two cubs with all of us watching in amazement. The tenderness she exhibited as she caressed her two children was very human-like, and again the tears came a-pouring!
Polar bears are dependent upon sea ice to survive. This specialized apex predator of the Arctic hunts ringed seals and bearded seals by waiting at seal breathing holes from their icy platform. No other food provides the necessary fat needed for polar bears to survive the harsh climate. The bears that live on Hudson Bay in Manitoba, Canada, are certainly no exception. Because of the currents and fresh water from the many rivers decreasing the salinity of the Hudson Bay, the ice there freezes earliest in the winter and melts the latest in the summer, making it an acceptable environment for the bears to come this far south. During this time when the ice has melted, the bears seek land, where they fast for the months until the ice forms again.
The bears of Hudson Bay are adapted to this normal fasting period of two to three months (six months for a denning female) and live off of the fat they accumulated while living on the sea ice during the winter. However, since the Industrial Revolution, humans have been steadily increasing the amount of carbon released into the atmosphere, which is warming the Earth and this is causing the ice to melt sooner and refreeze later. Since the late 1980s, the polar bears of Hudson Bay have experienced a one-week decrease in the presence of their sea ice per decade; this amounts to a 22 percent decrease in the ice and also a 22 percent decrease in the polar bear population. And the ice that is freezing each winter is getting smaller. As the water temperature rises, the ice will eventually not refreeze at all in the Hudson Bay, and that will mean no more polar bears there.
Over 90 percent of today’s scientists agree that the increase in global warming is human caused. A certain amount of greenhouse gases are natural and are necessary to keep our planet warm; it’s just that when you exceed the amount that our atmosphere can release naturally, they get trapped and cause all the trouble. The fundamental laws of physics state that the release of carbon into the atmosphere is causing our planet to warm up. As we warm, the ice melts in the Arctic, causing polar bears to lose their hunting ground. While on land, the bears lose an average of 2.2 pounds (1 kilogram) a day, so the longer the bears have to wait to eat, the thinner they become.
Female polar bears of good condition weigh between 440 and 660 pounds (200 and 300 kilograms). A bear that has successfully mated will not produce cubs if her body condition isn’t capable of handling another bout of fasting as she enters a den to have her young. Since polar bears experience delayed implantation, her body will reabsorb the fertilized egg if she isn’t physically able to bring the cubs to maturation. Scientists have concluded that a female bear must weigh at least 400 pounds (180 kilograms) in order to produce cubs. Doing the math, one can see that waiting longer and longer to eat will decrease cub births and expedite a population decrease.
The lives of polar bears and the survival of the arctic ecosystem is in our hands. This video on the Polar Bears International website shows the decrease in the sea ice in lapsed time. Look at the dates on the upper-right corner of the video to see the years. There were about 1,200 bears living in the Hudson Bay area in 1984, and the last count in 2004 was 935 bears.
No one can predict when the sea ice will be gone for good on the Hudson Bay, but scientists do agree that it will continue to melt if we don’t stop it. As daunting as that thought is, scientists also agree that this can be stopped, and there is great reason to hope if we act NOW! The carbon emissions that our planet can safely handle are 350 PPM (parts per million). We are currently at 380 PPM and steadily climbing. To get this number down to 350, we need to change our lifestyles and all work together toward carbon reduction. There are so many great things we can all do to help the situation, and I plan to address some of them in my next blog post, so please check back. The polar bears are counting on us!
Hali O’Connor is a senior keeper at the San Diego Zoo. You can also read blog posts from the other keepers attending Keeper Leadership Camp.