科学美国人60秒 气候变化会使鸟类的大脑缩小(2)（在线收听）

So the team decided to reanalyze that massive, original dataset—but this time, factor in brain size.

因此，研究小组决定重新分析这个庞大的原始数据集--但这一次，把大脑的大小纳入其中。

They found birds with larger brains in relation to their body size are shrinking at slower rates than birds with smaller brains.

他们发现，与大脑较小的鸟类相比，大脑较大的鸟类体型缩小的速度较慢。

And that was true even after controlling for other factors that could affect how quickly these birds are evolving, like generation time and mutation rate.

即使在控制了其他可能影响这些鸟类进化速度的因素后，比如生殖时间和突变率，情况也是如此。

But Botero says, just because these larger-brained bird species can temporarily buffer themselves from warmer temperatures, it doesn’t mean they’re completely protected from climate change.

但是博特罗表示，仅仅因为这些大脑较大的鸟类可以暂时缓冲温度升高的影响，但这并不意味着它们完全免受气候变化的影响。

It is important to realize that what we see here is not an indication that big brain birds are fine, and that they are not having any problems or that they are just capable to take whatever kind of change is coming from this suite of different environmental phenomena that is happening right now.

重要的是要意识到, 我们看到的不是这样的迹象--关于大脑袋的鸟类很好, 它们没有任何问题, 或者它们有能力接受目前正在发生的一系列不同的环境现象所带来的任何变化。

Still, the team says there’s still a lot to learn when it comes to the ways in which behavior could affect how birds species respond to climate change.

尽管如此，该团队表示，当涉及到行为如何影响鸟类对气候变化的反应方式时，仍有很多东西需要研究。

For one thing, in this study, there was only about a twofold difference in relative brain size between the species with the largest brain—the song sparrow—and the one with the smallest—the Swainson’s Thrush.

首先，在这项研究中，大脑最大的物种--歌雀--与大脑最小的物种--斯文森画眉鸟--之间的大脑大小只有大约两倍的差异。

That means the responses could be even stronger in birds with larger brains, like crows.

这意味着大脑更大的鸟类，比如乌鸦，这种反应可能更强烈。

We're sampling only a small amount of the potential variation in relative brain size here in our study.

在我们的研究中，我们只对大脑大小的一小部分潜在变化进行了采样。

And so that does suggest that even potentially small differences in relative brain size might actually have a large effect on ecological responses to climate change.

因此，这确实表明，即使是大脑大小的微小差异，实际上也可能对气候变化的生态反应产生巨大影响。

For now, Baldwin says, one of their key takeaways is that smaller-brained bird species could be particularly vulnerable as the climate continues to change.

鲍德温表示，就目前而言，他们的主要收获之一是，随着气候持续变化，大脑较小的鸟类可能特别容易受到伤害。

For Scientific American’s 60-Second Science, I’m Shahla Farzan.

谢谢大家收听科学美国人——60秒科学。我是沙拉·法尔赞。