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Benji Jones
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David Willard
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Mandi Nguyen
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Noam Hassenfeld
David Willard：在芝加哥市中心，长期以来收集了超过10万只死鸟用于研究，为发现鸟类体型缩小提供了数据基础。
Noam Hassenfeld：过去35年里，各种鸟类的体型都在缩小，这引发了人们对气候变化等环境因素影响的关注。
Benji Jones：研究表明，过去40年里，鸟类的平均体重减少了2.6%，腿长也缩短了2.4%。不仅鸟类，许多其他动物，如蝾螈、鱼类、老鼠、鹿、绵羊和蟾蜍等，体型都在缩小。气候变化可能是导致动物体型缩小的原因之一，伯格曼法则可以解释温血动物在温暖气候下体型较小的现象，但无法解释冷血动物体型缩小的现象。高温会加速冷血动物的新陈代谢，导致它们生长速度加快，体型变小。并非所有动物都在缩小，一些动物（如美洲貂和欧亚水獭）体型反而变大了，这说明动物体型变化的原因复杂多样，目前尚不清楚具体机制。动物体型缩小可能是进化适应的结果，也可能是环境变化导致的个体发育差异。动物体型缩小对生态系统的影响复杂且难以预测，气候变化对生物多样性的影响复杂且难以预测。
Mandi Nguyen：对未来动物形态的预测，需要考虑多种因素，包括动物的生存能力和未来的环境状况。科学家们从不同角度预测未来动物的形态，甚至考虑了地球以外的环境。黏菌的适应性强，其在火星上的进化难以预测。预测未来动物的形态有助于我们更好地理解进化过程以及人类活动对地球的影响，也有助于我们更好地应对气候变化等挑战。
David Willard: 'About 40 years ago, David Willard was working at the Field Museum in Chicago, this famous natural history museum, when he heard something strange.' 'Over the last few decades, David and other volunteers have collected over 100,000 dead birds across downtown Chicago.'
Noam Hassenfeld: 'Birds over the last 35 years have shrunk.' 'And this wasn't just one type of bird. The most amazing thing that they observed is that on all of the species, whether it was a thrush, a warbler, a sparrow, they were showing this declining size.'
Benji Jones: 'It's pretty significant. So they found that birds on average over this 40-year period lost about 2.6% of their mass.' 'It's pretty widespread. So it's not just birds that are shrinking. I've come across studies that show salamanders are shrinking over time. Fish, wood rats, deer, sheep, common toads.' 'There's been a fair amount of research on birds and some studies on mammals as well that appears to link these shrinking animals to global warming, to climate change.' 'So if you look at something like frogs... What researchers have found is that when it's hotter, their metabolism speed up.' 'Yeah, so there hasn't been a ton of research, but I have seen a couple studies. One was on the American marten, which is this cute ferret-like animal. And then another was on the Eurasian otter, also a very cute animal.' 'So it seems like global warming could be changing the shape of animals over time, but we don't really know which rules apply to which specific animals and exactly how they apply.' 'So for frogs, for example, and other amphibians, that seems to be the case.' 'And even more importantly is that some animals are getting smaller at a faster rate than others. Some animals are even getting bigger and that creates big problems at an ecosystem level.'
Mandi Nguyen: 'The Earth, millions of years in the future. This blue planet still teems with life forms, but humans are not among them.' 'And so we now have an atmosphere that's richer in oxygen than the one that we have now. Plants have flooded the atmosphere with oxygen, reshaping life on the Earth's surface.' 'So this whale rat has evolved to become fully aquatic. So it's lost its fur, it's lost its whiskers, you know, it's all gone.' 'It's definitely more speculation than definitive prediction.' 'Life is probably going to persist, and any future animal or ecosystem that exists is going to be impacted by what happens today.'
Deep Dive
Scientists have noticed that birds and various other animals are shrinking over time, possibly due to climate change. This phenomenon is widespread and involves both warm-blooded and cold-blooded creatures.
Shownotes Transcript