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随身英语The problem with big brains 聪明大脑所带来的问题 Play audio file研究显示，有一个体积较大的大脑可能是造成一些大型哺乳动物灭绝的原因之一。这是因为大脑工作时需要消耗许多能量，再加上大脑体积大的动物通常有着较长的妊娠期，这也就意味着它们繁殖得很慢。本期《随身英语》探讨大体积大脑所引起的困扰。 课文内容 词汇: 生物 Is it possible to be too clever? Could it be that a big brain is actually a dangerous asset? Whilst the brainy human species goes from strength to strength, a study suggests that having an abundance of grey matter directly increases the risk of extinction in our mammal cousins. Biologist Manuela Gonzalez-Suarez, from the University of Reading, says that big brains come with a clear downside. "The cost is too high," she told BBC Future. They require a lot of energy to grow and maintain. Large-brained animals also have longer gestational periods, meaning they produce fewer offspring. And their young need greater parental attention until they become independent. These traits mean "populations cannot grow fast, or quickly compensate for additional mortality," she says. In short, big brains are an investment not all animals can afford. And this precarious situation is made worse by the fact that many large mammals are themselves the target of poaching or live in threatened habitats. | 
