NEWSDate: 02/06/14 11:58:00 AMBy: Courtney Todd (mailto: toddc2@mail.uc.edu)Phone: (513)-675-9616

The Polar Bear Hunger GamesWhat Scat Tells Us!

As polar bears drift away on ice with the inability to hunt for food, you have the ability to order your favorite carry-out. Climate change isnt affecting the way you eat. But, it is affecting the diet of the species scientists call, Ursus maritimus. The ice in western Hudson Bay melts completely by mid to late July forcing polar bears ashore and away from their primary prey. With ice break up occurring faster than usual, polar bears are left with less time to hunt for seals and prepare for winter. Although polar bears make it ashore, they are in a negative energy balance. This means they are primarily living off of fat reserves until new prey is observeda form of fasting. Polar bears period onshore is projected to increase as the western Hudson Bay climate continues to warm up causing ice breakage. Zoologists from the American Museum of Natural History, Linda J. Gormezano and Robert F. Rockwell, examined polar bear scata fancy term used to describe animals fecal droppingsfrom the western Hudson Bay area to determine their terrestrial diet. Their research was recently published in the journal, Ecology and Evolution. Defining how the terrestrial diet might have changed since the onset of rapid climate change is an important step in understanding how polar bears may be reacting to climate change says Linda Gormezano.Scat sampling occurred along 160 km of coastline and adjacent inland areas of what is now termed the Cape Churchill Peninsula where polar bears are known to occur during the ice-free period in western Hudson Bay. They chose to include inland and denning habitats so they could provide a complete inventory of the land based diet of all demographic groups that use the region. A polar bear looks up from the recently killed caribou it was eating at Keyask Island (58.16958N 92.85194W) on July 26, 2010. Photograph by R. F. Rockwell.

Gormezano and Rockwell characterized the current scat from polar bears in the Hudson Bay area while evaluating samples from a similar study conducted 40 years ago. They chose to examine a study from the past, before climate change was affecting the western Hudson Bay lowlands. Today, they found that caribou and snow geese are abundant resources for polar bears on land. The study from the 1960s showed no signs of caribou and considerably less signs of snow geese. The new research indicates that some polar bears in the western Hudson Bay area are using foraging strategies while pushed ashore, such as prey-switching and eating a mixed diet of plants and animals to survive in their rapidly changing environment. This behavior likely derives from a shared genetic trait with brown bears from which polar bears separated at least 600,000 years ago. Gormezano and Rockwell suggest that the polar bears foraging behavior is a response to nutritional stress.The current threats to polar bears in the western Hudson Bay area are clear as the ice break season expands, limiting polar bears access to seals. Rockwell says, There is little doubt that polar bears are very susceptible as global climate change continues to drastically alter the landscape of the northern Polar Regions. But were finding that they might be more resilient than is commonly thought. In fact, polar bears hunted caribou and snow geese when seals were still available on ice. This shows more support for their foraging behavior and prey switching abilities. Fortunately, most of the polar bears become optimistic omnivores and adapt to other plants and animals such as, caribou and snow geese. Still, we need to keep in mind that polar bears are listed as Endangered Species under the United States Endangered Species Act. Rockwell and Gormezano suggest to continue their research by studying the amount of polar bears shifting their diet and the nutritional gain that comes with the terrestrial diet. Perhaps that research would show the survival rates of polar bears once they forage on land. ###_________________________________________________________________________________________________________Support of Gormezanos and Rockwells research was primarily provided by The Hudson Bay Project. Additional funding was provided by American Museum of Natural History Theodore Roosevelt Memorial Grant (#0655), Arctic Institute of North America Grants-In-Aid, Churchill Northern Studies Centre Northern Research Fund, City University of New York and Manitoba Conservation Sustainable Development Innovations Fund (#27070).