每次看到那些家伙在天上飞，我就纳闷，鸽子怎么那么大？说实话，我小时候就挺好奇的，那时候我就想，是不是因为鸽子成了人类的信使，所以长得比较大，便于携带信件。
前几天和一位退休的鸟类学家聊天，他给我解答了这个疑问。他说， pigeon size actually has to do with its ability to carry food. Pigeons are known for being geolocators, meaning they can find their way home from miles away. And to make that possible, they need to carry food for the journey, which means they need a bigger body to store the calories. My guess was right, but there’s more to it than that.
然后他告诉我，其实鸽子的大小也在一定程度上是人为选育的结果。当年 humans had some unhealthy habits with pigeons. We used to participate in pigeon racing, and in the competitions, bigger pigeons had an advantage because they could carry feed for longer. So, over time, bigger pigeons became more popular in the pigeon community. There you go, another reason we see them so much bigger than their smaller bird friends!
我听得一脸懵，觉得这也太real了。想想看，我们现在养的小狗，不也都是人类刻意培育出来的吗？好像一提到“人类影响”，啥生物就莫名变大了似的。不过这也挺有意思的，说明我们和动物之间的互动挺深的，不是吗？
然后他自己也开始感慨，说现在的鸽子变大，也是一种“悲哀”。他认为，鸽子的基因原来设计得挺好的，现在为了人类的需求，长得越来越大，生存能力反而下降了。哎，谁说不是呢，现在越来越多的动物，都是在为我们人类的需求而改变。
最后，他还建议，我们应该多关注这些动物，它们也都有自己的生态位和故事。所以说，下次再看到天上飞来飞去的大家伙，就知道它们为什么那么大了。