在线英语听力室_免费在线英语听力学习网站

This is Scientific American — 60-Second Science. I'm Christopher Intagliata.

这里是科学美国人——60秒科学。我是克里斯托弗·因塔利亚塔。

Just like humans have virtually unique sets of fingerprints¹, every giraffe has a unique set of spots. Not that those spot patterns really help wildlife biologists identify their study subjects in real time.

就像人类拥有独特的指纹一样，每只长颈鹿身上都有一组独特的斑纹。但并不是说这些斑纹图案能帮助野生动物生物学家立刻识别出他们的研究对象。

"We have more than 3,000 individuals. ...so I have a hard time myself keeping track of that many humans so I have that problem with giraffes patterns as well."

“我们有3000多人，我很难记住那么多人，记住长颈鹿的斑纹图案同样很困难。”

Derek Lee is a wildlife biologist and population ecologist at Penn State, and with the Wild Nature Institute, a research consultancy group. He and his collaborators have been tracking giraffes for seven years, throughout 1,500 square miles in Tanzania. And they've amassed² a library of 70,000 giraffe photos along the way. Photographing the animals isn't that hard, he says.

德里克·李是宾夕法尼亚州立大学及研究咨询组织野生自然研究所的野生动物生物学家和种群生态学家。他和合作者在坦桑尼亚1500英里的土地上追踪了长颈鹿7年。在追踪过程中，他们收集了7万张长颈鹿图片。他说，拍摄长颈鹿并不太难。

"The hard part is the tsetse flies constantly biting us on our face and hands while we're trying to take pictures."

“最难的是在我们想拍照时，采采蝇不停地叮咬我们的脸和手。”

Now, they've used image analysis software to study the spots of mothers and their calves³. And they found that baby giraffes inherit at least some particular elements of their patterning from their moms. Like how circular the spots are, and how jagged the edges are.

现在，他们通过图像分析软件来研究长颈鹿妈妈及其幼崽的斑纹图案。他们发现，小长颈鹿从其母亲那里遗传了斑纹图案，至少是某些特定元素的斑纹。比如斑纹的环形方式以及边缘锯齿的样式。

They also found that calves with larger spots were more likely to survive their first months on the savannah, perhaps because the spots better mimic⁴ the dappled sunlight in the bushes where calves like to hide from hungry lions and hyenas⁵.

他们还发现，斑纹较大的幼崽更可能在大草原上生活的头几个月里存活下来，也许是因为这些斑纹更像灌木丛中斑驳的阳光，而幼崽喜欢藏在灌木丛中躲避饥饿的狮子和鬣狗。

The results - and a lot of giraffe patterns - are in the journal PeerJ.

研究结果以及大量长颈鹿斑纹图案刊登在《PeerJ》期刊上。

It's perhaps not surprising that a physical characteristic that protects an individual from being eaten passes the test of Darwinian natural selection - and get passed along to offspring. "The fact these things are heritable and they did affect juvenile⁶ survival makes us feel like evolution is acting⁷ on these spot traits." So if mom's camouflage⁸ is good, her babies, too, might have the spots that make them harder to spot.

保护个体不被吃掉的身体特征通过了达尔文自然选择的考验，这种特征之后又遗传给了后代，这或许不足为奇。“事实上这些特征可以遗传，而且确实对幼崽的存活产生影响，这令我们感觉进化是围绕这些斑纹特征进行的。”因此，如果长颈鹿妈妈的伪装本领高强，那其幼崽可能也会拥有很难被发现的斑纹。

Thanks for listening for Scientific American — 60-Second Science Science. I'm Christopher Intagliata.

谢谢大家收听科学美国人——60秒科学。我是克里斯托弗·因塔利亚塔。