Walruses Killed in Global Warming Stampede

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What comes to mind when you think of a deadly stampede? Cattle? Buffalo? A year-end sale at Barneys?

Certainly not walruses, right? But yet, thousands of them died this past spring on the Russian side of the Bering Strait — from a stampede that scientists say is a direct result of global warming.

Walruses are big-tusked mammals who, unlike seals, are unable to swim indefinitely, They typically use sea ice to rest or haul themselves onto land for a few weeks at time. (You may recall a poignant CG graphic in “The Inconvenient Truth” of a polar bear attempting to climb on various pieces of ice, only to have them crumble into pieces.)

But as ice disappears, walruses have been forced to come ashore in both Russia and Alaska in alarming numbers — with herds as large as 40,000. Scientists are finding it even more startling that walruses have been spotted in locations not used as “haulout” places in centuries. Because walruses are now spending so much time on shore, they have a higher chance of coming into contact with humans, other artic animals like polar bears, or being startled by low flying aircrafts and noise from boats, which can easily cause them to stampede. Due to the size and weight of walruses (and the fact that they congregate close together when on shore), hundreds of animals can be injured or killed in these mad, panicked dashes, with calves or weaker animals fairing the worst.

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The long-term effects of diminished sea ice is more problematic than just stampedes. Female walruses usually stay with the sea or travel north with their pups in the spring, while males remain in the Bering Strait or on shore. Traditionally, as the ice moves over the shallow continental shelf, calves rest along this ice, while females dive for clams, snails, and other bottom creatures as a food source. With the retreat of ice in recent years, the ice edge has been pushed far north of the continental shelf in waters that are several thousands of feet deep, too deep for walruses who can only dive a few hundred feet to feed. As more walruses are unable to find food, the fear is that mothers and calves will starve or be forced ashore with the males, as is currently being reported.

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These walruses will then be forced to swim farther to forage for food, requiring more energy. Scientists predict an increased mortality rate — especially for young calves who are used to resting on ice and will now attempt to travel long distances as they stay by their mother’s side. The death of young calves and females is even more problematic when compounded by the fact that female walrus only births one calf every two years and males do not mate until they reach sexual maturity at 15 years of age. The slow breeding habits of walruses and their traditional hunting by Eskimos for their tusks and food have already caused the walrus to be listed as endangered.

It is believed that only 250,000 Pacific and even fewer Atlantic walruses exist today. And global warming is threatening to push the walrus closer even to extinction.

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No matter how you look at it, less ice equals a higher risk of walrus mortality. Lack of food and starvation, or exhaustion and stampede all predict poorly for the future of the walrus. According to the National Snow and Ice Data Center at the University of Colorado at Boulder, Arctic sea ice during the 2007 melt season plummeted to the lowest levels since the first satellite measurements in 1979. The average ice extent this September was 1.65 million square miles — which sounds like a lot of coverage, but is actually the lowest on record in September. Furthermore, Scientists estimate the rate of sea ice decline is now ten percent, or 28,000 miles per year!

At that rate, walruses will surely be joining the likes of other sea creatures already on the brink of extinction. It is time to look at the big picture. We have literally forced age-old ice caps to melt, and gentle creatures like walruses — whose only predators are polar bears, killer whales, and man — to march ashore for suicidal stampedes.

It is time for change, because as the ice in the sea melts, so does the positive outlook for the fate of the walrus.



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