Jeff Danziger lives in New York City. He is represented by CWS Syndicate and the Washington Post Writers Group. He is the recipient of the Herblock Prize and the Thomas Nast (Landau) Prize. He served in the US Army in Vietnam and was awarded the Bronze Star and the Air Medal. He has published eleven books of cartoons and one novel. Visit him at DanzigerCartoons.com
By Michael Muskal, Los Angeles Times (TNS)
The number of polar bears in eastern Alaska and western Canada has declined by 40 percent, according to a scientific study that raises more questions about the impact of global warming on the creature that has become the symbol of some of its worst effects.
The study, published in the current issue of Ecological Applications, was carried out by scientists from several groups, including the U.S. Geological Survey and Environment Canada, that tagged and released polar bears in the southern Beaufort Sea from 2001 to 2010. The bear population in the area shrank to about 900 in 2010, down from about 1,600 in 2004, according to the findings.
Perhaps even more worrisome, just two of 80 polar bear cubs that the international team tracked between 2003 and 2007 survived, according to the study. Normally about half of the cubs live.
“Climate change is not some future threat,” Sarah Uhlemann, senior attorney for the Center for Biological Diversity, one of the groups that has been fighting to save polar bears, told the Los Angeles Times. “Global warming is happening now and killing polar bears now.”
Polar bears have long been followed as scientists watch for early signs of global warming. The bears are especially at risk as Arctic ice melts.
They spend much of their waking lives on Arctic sea ice floes, eating seals that are also dependent on sea ice. As the ice has dramatically shrunk, the bears have been forced into long, painful swims in search of new ice. One of the marathon aquatic excursions in 2011 lasted nine days and 426 miles; the mother lost 22 percent of her body weight and her cub died.
Groups have been fighting for years in the courts to protect the bears and have won a threatened status for them under the federal Endangered Species Act. Groups have been seeking even more protection, and the latest data could be part of a push to get the bears placed on the endangered species list, Uhlemann said.
“Global warming has put Alaska’s polar bears in a deadly downward spiral,” Uhlemann said. “If we don’t act now, we will lose polar bears in Alaska.”
Polar bears suffered particularly low survival rates between 2004 and 2006, when “unfavorable ice conditions” limited their access to ice seals, their favored prey, according to the study.
The bear population in the southern Beaufort Sea appears to have stabilized between 2008 and 2010, according to scientists. They said the stabilization appeared to be due to unusual oceanographic conditions, less competition or behavioral changes. Some polar bears stayed on land during the summer, feeding on subsistence-hunted bowhead whale carcasses.
“Given projections for continued climate warming,” these changes are “unlikely to counterbalance the extensive habitat degradation projected to occur over the long term,” the report found.
Conservationists have predicted that more than two-thirds of the world’s polar bear subpopulations could be extinct by 2050.
“We’re very worried that eastern Alaska’s polar bears may be among the first to go,” Uhlemann said. “The United States and the world have to get serious about reducing greenhouse gases if we want polar bears to survive.”
Photo: Ansgar Walk via Wikimedia Commons
By Yereth Rosen, Alaska Dispatch News, Anchorage (MCT)
Polar bears looking for mates appear to be following their noses over the sea ice, according to a newly published study.
Like brown and black bears, polar bears make a practice of sniffing scents left behind by other members of their species. But unlike brown and black bears, which leave their odors on trees or other vertical surfaces, polar bears have to rely on paw prints left on the horizontal surface of snow-covered ice.
They appear to be using these scents to decipher messages about the other polar bears that are nearby, according to the study by scientists from the San Diego Zoo’s Institute for Conservation Research, Polar Bears International and the U.S. Geological Survey. The study was published online in the Nov. 3 issue of the Journal of Zoology.
The study used smell swabs collected from the feet of tranquilized Chukchi and Beaufort bears sampled between 2004 and 2009. The Arctic field work on the wild bears was done by the U.S. Geological Survey and the U.S. Fish and Wildlife Service. In all, the agencies took samples from about 200 Beaufort bears and about 100 Chukchi bears.
The preserved odors from the bears’ feet were strong and “generally unpleasant,” said the lead author, Megan Owen of the Institute for Conservation Research at San Diego Zoo Global.
“We don’t know the ultimate source of the scent, but it is possible that it is an accumulation of urine or body odor, a collection of apocrine gland secretions (sweat) or a combination of both,” she said in an email.
The paws’ smelly secretions, preserved and stored in deep-freeze, were spread on cardboard — considered a neutral surface — and placed in boxes that were presented at different times of the year to 26 polar bears in 10 zoos in locations ranging as far south as Memphis and San Diego and as far north as Toronto and Quebec.
Once they presented the boxes, the scientists watched the zoo bears’ reactions.
They measured the number of approaches, the amount of time spent sniffing to investigate and a physical behavior called the “flehmen” response, in which mammals curl their lips, raise their heads and inhale through their mouths — a sign of keen interest.
Though the people conducting the experiments couldn’t distinguish between paw scents, the zoo bears could, the study findings suggest.
The scientists found that the zoo bears were most likely to investigate the scents of opposite-sex wild bears in the spring — the polar bear mating season. The male zoo bears seemed to be able to identify which smell was left by female bears in estrus.
The findings raise some concerns, said the authors.
If the sea ice is serving as polar bears’ smell-message board, that could spell trouble for the animals, Steven Amstrup, chief scientist for Polar Bears International and a co-author of the scent study, said in an email.
“The spring sea ice is far less extensive and more fragmented than it was historically. I saw its character change dramatically during the 30 years I did polar bear research in Alaska,” said Amstrup, who spent several years studying polar bears for the USGS’s Alaska Science Center. “Such fragmentation can only worsen as the world warms, and any scent trails left on the ice will become more fragmented. I cannot hypothesize how increasing fragmentation could make trails anything but more difficult to follow.”
Photo: Ansgar Walk via Wikimedia Commons
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