科学美国人60秒 SSS 长颈鹿妈妈的基因使得小长颈鹿很难被发现

Mom's Genes 1 Make Some Giraffes Hard to Spot

Just like humans have virtually unique sets of fingerprints 2, every giraffehas a unique set of spots. Not that those spot patterns really help wildlife biologists identify their study subjects in real time.

"We have more than 3000 individuals. … I have a hard time keeping track of that many humans so I have that problem with giraffes as well."

就像人类有独特的指纹一样，每只长颈鹿都有独特的斑点。并不是说这些斑点模式真的能帮助野生动物生物学家实时识别他们的研究对象。“我们有3000多人。他说:“我不知道长颈鹿是什么动物。我很难跟踪那么多人类，所以我对长颈鹿也有同样的问题。”

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 1500 square miles in Tanzania. And they've amassed 3 a library of 70,000 giraffe photos along the way. Photographing the animals isn't that hard, he says.

德里克·李(Derek Lee)是宾夕法尼亚州立大学(Penn State)的野生生物学家和种群生态学家，他就职于研究咨询机构野生自然研究所(Wild Nature Institute)。他和他的合作者在坦桑尼亚1500平方英里的土地上追踪长颈鹿已有7年了。他们沿途收集了7万张长颈鹿的照片。他说，拍摄这些动物并不难。

"The hard part is the tsetse flies constantly biting us on our face and hands while we're trying to take pictures."Now, they've used image analysis software to study the spots of mothers and their calves 4. And they found that baby giraffes inherit at least some particular elements of their patterning from their mothers. Like how circular the spots are, and how jagged the edges are.

“最难的部分是采采蝇在我们拍照的时候不断地咬我们的脸和手。”现在，他们使用图像分析软件来研究母象和幼象的斑点。他们发现小长颈鹿至少从它们的母亲那里遗传了一些特定的模式元素。就像斑点是多么圆，边缘是多么锯齿状。

They also found that calves with larger spots were more likely to survive their first months on the savannah, perhaps because the spots better mimic 5 the dappled sunlight in the bushes where calves like to hide from hungry lions and hyenas 6. The results—and a lot of giraffe patterns—are in the journal PeerJ. [Lee et al, Seeing spots: quantifying mother-offspring similarity and assessing fitness consequences of coat pattern traits in a wild population of giraffes (Giraffa camelopardalis)]

他们还发现，斑点较大的幼仔更有可能在大草原上度过头几个月，也许是因为这些斑点更像灌木丛中斑驳的阳光，幼仔喜欢躲在那里躲避饥饿的狮子和鬣狗。结果——以及许多长颈鹿图案——刊登在PeerJ杂志上。

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 juvenile 7 survival makes us feel like evolution is acting 8 on these spot traits." So if mom's camouflage 9 is good, her babies, too, might have the spots that make them harder to spot.

保护一个人不被吃掉的身体特征通过了达尔文自然选择的考验，并遗传给了后代，这也许并不奇怪。“这些东西是可遗传的，它们确实影响了青少年的生存，这让我们觉得进化是根据这些斑点特征进行的。”因此，如果妈妈的伪装很好，她的孩子也可能有斑点，使他们更难发现。