Most polar bears follow the sea ice as it grows and melts (融化) throughout the year. They depend on sea ice as the platform from which they hunt for sea animals. But as global temperatures have been rising, sea ice has been disappearing. And some bears have traveled so far in search of ice that they risk dying of hunger.
But in southeast Greenland, where the sea freezes over for just a few months, some polar bears are subsisting locally. Polar bears here have adapted to hunting from the glacial mélange, which is a mix of ice, snow and slush (雪泥). “These polar bears are residents of sea ice-free areas for more than eight months of the year,” says the biologist Kristin Laidre. “Normally, a polar bear wouldn’t be able to live without sea ice for that long.”
In northeast Greenland, the distance traveled by bears was 40 kilometers every four days. But in the southeast, the distance traveled was just one-fourth of the distance.“Apparently, those southeast Greenland bears are able to use resources that are present, so that they don’t have to make these big movements,”says Steven Amstrup, a zoologist. They make the sea ice home for a few months each winter and spring. For the rest of the year, the bears hunt from the glacial mélange. They use it just like sea ice.
However, researchers say that most polar bears will die out by 2100 unless emissions (排放) of climate-warming greenhouse gases are sharply cut back. Southeast Greenland and similar, small regions could become the last places for some of the remaining polar bears. Yet even they will disappear if climate change continues to melt the sea ice on which this species depends.
“Despite having learned to adapt to their slushy world, southeast Greenland polar bears will die without human climate action,” Amstrup says. “The glacial mélange isn’t widespread in the regions around the North Pole. And it could disappear if temperatures rise much more. Polar bears still suffer hunger.”
12. What is the problem with polar bears nowadays?
A.They hunt for food in polluted areas. |
B.They can hardly adapt to a new environment. |
C.They lose their living space to some sea animals. |
D.They have difficulty hunting due to the loss of sea ice. |
13. What does the underlined word “subsisting” in Paragraph 2 mean?
A.Escaping. | B.Surviving. | C.Suffering. | D.Attacking. |
14. Why do those southeast Greenland bears travel less far?
A.They have poor swimming ability. |
B.They depend on existing resources to hunt. |
C.They change their diets at different times of the year. |
D.They need to produce babies in familiar environment. |
15. What may be largely responsible for the reduction in bear populations?
A.Human hunting. | B.Natural disasters. |
C.The industrial farming. | D.The warming climate. |