Sep. 10, 2012

Foresight in the Arctic: Predation and Preservation

by Kara Rogers

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The Arctic wolf is a skilled hunter and a resourceful predator. It pounces on Arctic hares and lemmings, chases down large mammals like caribou, and scavenges seals and other marine mammals. The Arctic wolf is also a major predator of the musk ox, and during the summer, tender musk ox calves may make up a significant portion of the Arctic wolf's diet.
To catch one of these youngsters, however, Arctic wolves must first get past the adult musk oxen, each of which is three to four times the wolf's size and is equipped with intimidating horns. When they sense danger from wolves, the adults gather into a defensive formation, encircling the young and lowering their horns to their attackers.
Penetrating this formidable formation presents a considerable challenge for Arctic wolves, one that has led biologists to speculate about whether wolves use cooperative strategies to hunt musk oxen. Strategies such as ambushing or attacking from multiple directions at once presumably would enable a pack of wolves to capture a musk ox calf more effectively than if they were to simply chase after it.
But in the wild, wolves only rarely have been observed to use cooperative strategies when hunting. As biologist L. David Mech and others have pointed out, this may be because cooperation requires higher cognitive processes. To plan an ambush, for example, Arctic wolves would need to think ahead. They would need foresight.
In 2007 Mech reported on two instances in which Arctic wolves on Ellesmere Island, in the Canadian High Arctic, appeared to use foresight and planning to hunt musk oxen. In one of these instances, a pair of wolves spotted a herd of musk ox and proceeded to wait at the edge of a meadow that the herd eventually would pass through. When the musk oxen finally came near enough, the wolves attacked. Their ambush, however, was thwarted by the herd's rapid defense response.
While the extent to which wolves use foresight to hunt musk ox remains unclear, the ability to think ahead comes into play in other ways in the Arctic. Of particular importance is human foresight. Scientists' ability to model climate change, for instance, has revealed that global warming could have severe consequences for Arctic ecosystems. By looking ahead to the future, however, scientists have also discovered that this disaster can be avoided.
One threat to the Arctic is carbon dioxide released into Earth's atmosphere as a result of human activities. Carbon levels reached an all-time high -- 400 parts per million (ppm) -- in Alaska this past spring. That figure represents a 45 percent increase in atmospheric carbon levels within the last two centuries alone (since the Industrial Revolution). Scientists have found, however, that a reduction to 350 ppm would be sufficient to stop climate warming. Reaching this level could potentially restore Arctic sea ice and mitigate potential warming-associated declines in populations of large Arctic mammals, such as musk oxen, that could in turn alter the range and population sizes of predators like the Arctic wolf.
Reaching 350 ppm might seem impossible to some. But it can be done, if we make a conscious effort to reduce our individual carbon dioxide emissions. This is can be accomplished in a variety of ways, such as by replacing incandescent light bulbs with energy-efficient compact fluorescent light bulbs and by using dishwashers, washing machines, and dryers only when a full load is ready.
To learn more about your individual carbon dioxide emissions, check out the EPA's Household Carbon Footprint Calculator.



About Kara Rogers

Kara is a freelance science writer and senior editor of biomedical sciences at Encyclopaedia Britannica, Inc. She is the author of Out of Nature: Why Drugs From Plants Matter to the Future of Humanity (University of Arizona Press, 2012).

The views expressed are those of the author and are not necessarily those of Science Friday.

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