Các nhà khoa học theo dõi con gấu bắc cực bơi 9 ngày

Scientists track polar bear's nine-day swim

Scientists working in the Arctic have tracked a polar bear that swam non-stop for nine days. A US team followed the bear in 2008, as it left Alaska and swam north to the sea ice. They published details of the feat in the journal 'Polar Biology'.

Polar bears are superb swimmers. But their hunting ground is the surface of the Arctic ice, where resting seals make easy and calorie-rich prey. In the summer though, a swim between ice floes to catch seals can turn into a marathon.

The researchers fitted the female bear with a radio collar, and tracked her as she swam continuously for nine days - the longest polar bear swim ever recorded. She covered almost 700 km in waters as cold as 2C. Then she hauled herself out of the water and travelled a further 1,800 km - intermittently swimming and walking on the surface of the ice.

When the team recaptured the bear, she had lost almost a quarter of her body weight and her year-old cub, which had been travelling alongside her, had disappeared.

The scientists say that the retreating Arctic ice could be forcing polar bears to take greater risks in search of food, embarking on ever more perilous long-distance journeys.

Từ mới

superb

very good indeed

calorie-rich

full of calories, which provide energy

prey

animal which is being hunted by people or another animal

ice floes

large areas of ice which float on the sea

hauled

pulled or carried with great effort

intermittently

sometimes or occasionally

cub

here, young polar bear

retreating

melting ice

embarking

starting, beginning, or setting off

perilous

very dangerous