托福听力

🎧 听力原文

Narrator: Listen to part of a lecture in a biology class. Professor: So, we've been discussing how animals adapt to their environments. Today, let's talk about a fascinating example: the Arctic fox. This small mammal lives in the tundra, where temperatures can drop to minus fifty degrees Celsius. To survive, the Arctic fox has several remarkable adaptations. First, its fur changes color with the seasons—white in winter to blend with snow, and brown in summer to match the rocks and plants. This is a form of camouflage. But there's more. The fox's body shape is compact, with short ears and a short muzzle, which reduces surface area and minimizes heat loss. Also, its paws are covered with thick fur, allowing it to walk on ice without freezing. Interestingly, the fox also has a countercurrent heat exchange system in its legs. Warm blood from the body heats the cooler blood returning from the paws, which keeps the core warm while the paws stay cool. This prevents excessive heat loss. So, in essence, the Arctic fox is a master of thermal regulation. Now, can anyone think of a potential challenge this fox might face if the climate warms?