Nghe TOEFL

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Listen to part of a lecture in a biology class. Professor: Today we're going to talk about a fascinating adaptation in some desert animals: the ability to survive without drinking water for extended periods. Take the kangaroo rat, for example. This small rodent lives in the arid regions of North America. It gets virtually all its water from the metabolic breakdown of the seeds it eats. During digestion, carbohydrates are converted into carbon dioxide and water. This process, called metabolic water, provides about 90% of its water needs. Additionally, kangaroo rats have highly efficient kidneys that produce extremely concentrated urine, minimizing water loss. They also avoid daytime heat by staying in underground burrows, which are cooler and more humid. This behavior reduces evaporation from their lungs and skin. Interestingly, they have no sweat glands, so they lose very little water through perspiration. These combined adaptations allow them to thrive in environments where surface water is absent for months.