英语听力：自然百科 北极熊 冰上间谍 Spy_Bear—9（在线收听）

 It’s seaweed. Kelp is not wildly exciting, but it does contain carbohydrates and some protein too. The cub must find acrobatics rather strange. Hungry bears eat virtually anything. It’s a question of making the most of what’s around, and it’s never too soon to start hunting. Polar bears investigate almost every unfamiliar sight and smell. They are the most curious subjects ever filmed by spycams. This fascination suggests a surprising intelligence, one that evolved for the extraordinary challenges of hunting on ice. Ice floes present real difficulties for a predator, continually changing their shape and form. Seals are also tricky prey. In open water, they’re just too agile to catch. It becomes a little easier when they haul out on ice, but they hug the water’s edge for a quick escape. The bear immediately has a problem. There is no cover between him and his prey. He wrong-foots the seal by seemingly walking away