评论
打印
Winter is officially here in the Northern Hemisphere and for a bunch of us that means some cold weather.
北半球的冬季正式来到了，而对于我们来说冬季就意味着寒冷。
So it's the perfect time for news about hibernating animals and some huge penguins.
所以现在是播报冬眠动物和一些巨型企鹅大新闻的好时机。
During the winter, you and I can throw on an extra layer or crank up the heat
冬季，我们的外套加一层，再把暖气调到最大
but some animals survive frigid temperatures by hibernate.
但一些动物通过冬眠度过寒冷的冬季。
Hibernation is a kind of whole body slow down, where animals lower their metabolisms
冬眠时，整个身体放缓，动物放慢自己的新陈代谢
and just chill for a while literally.
让自己凉快一下。
And their body temperatures fall sometimes to below freezing,
有时它们的体温会降至零点以下，
I don't know about you but to me that sounds really unpleasant.
不知道大家感觉怎样，但对我而言，这听起来不是件愉快的事。
But how do hibernators handle it?
但冬眠的动物是怎么应对的呢？
Well, on Tuesday biologists at Yale announced in the Journal Cell Reports
周二，耶鲁大学的生物学家在《Cell Reports》杂志中宣布
that they've discovered part of the secret behind this ability to withstand the cold.
他们发现了抵挡严寒能力背后的部分秘密。
The team worked with a few rodents to figure out what's going on.
团队利用一些啮齿动物弄清楚了这是怎么回事。
Some of them hibernate, like the Syrian hamster and the 13 lined ground squirrel,
一些动物，如叙利亚仓鼠和13条纹地鼠（以它们身上的条纹命名），
which is named for its many stripes and others don't like lab mice.
以及其他种类的老鼠（非实验室老鼠）。
First, the researchers tested the animals' temperature preferences
首先，研究员对动物的温度喜好进行测试
by putting them in a chamber with two temperature controlled plates and measuring the time spent on each one.
他们将动物放入有两个温控盘的地方并计算它们在每个盘子上停留的时间。
One plate was a balmy 30 degrees while the second was colder and varied, sometimes getting as low as freeze.
一个盘子是温和的30度，而第二个盘子更冷且温度不定，有时甚至会低至零点。
For the most part, the mice stayed glued to the warm plate while the two hibernating species didn't really care
大多数情况下，老鼠会黏在温暖的盘子中，而两个冬眠物种对温度漠不关心
until the second plate got pretty cold about five or ten degrees.
直到第二个盘子变得相当冷，只有5或10度。
This nonchalance was very similar to mice that were genetically engineered to be missing a protein known as TRMP8,
这种漠不关心和某种老鼠相似，这种老鼠的基因中缺乏一种被称为TRMP8的蛋白质
suggesting that the protein might be able to explain some things.
而这暗示着，这种蛋白质胡须能够解释些什么。
TRMP8 is an ion channel in neurons that opens up in response to cold,
TRMP8是神经元中的一个离子通道，遇冷时，通道就会打开，
letting ions rush in so the cells transmit a signal to the brain and spinal cord.
让离子冲进来，这样细胞就能向大脑和脊髓传播信号。
The channel also responds to menthol that molecule from minty oils
通道还会对薄荷脑做出反应，一种来自薄荷油的分子
and a synthetic supercooling chemical called icilin.
以及一个合成过冷的化学物质——icilin。
Humans use a version of this receptor to sense cold, too.
人类也利用某个版本的感受器感知寒冷。
Biologists thought the hibernators might have fewer of these receptors
生物学家认为冬眠动物身上的感受器较少
which would explain why they didn't respond as much to cold.
这就能解释为什么它们对寒冷不敏感。
The squirrels and hamsters had just as many as the mice,
松鼠和仓鼠的传感器和老鼠一样多，
instead the receptors themselves were less sensitive to cold.
除了感受器，它们本身对寒冷就没那么敏感。
Neurons from each of the species responded the same to icilin which means they do work
各动物身上的神经元对icilin的反应相同，这意味着它们确实起作用了
but the hibernators' neurons responded much less to the same amount of cold.
但冬眠动物的神经元对相同程度的寒冷却没那么敏感。
Additional experiments revealed that most of the difference in temperature sensitivity
补充实验显示温度灵敏度的差异大部分
came from just 6 amino acids in the receptor protein.
来源于受体蛋白质中的6个氨基酸。
While the results don't explain why ground squirrels and hamsters start to get chilly below about 10 degrees,
而此结果并不能解释为什么地松鼠和仓鼠在约10度以下才感觉到寒冷，
it's one of the few times, scientists have been able to pin down a molecular adaptation for hibernation.
科学家已经能够阻止冬眠的分子适应。
Last week we also learned a lot about penguin evolution.
上周我们了解了很多关于企鹅进化的事。
Paleontologists in New Zealand reported the discovery of a new species of ancient penguin
新西兰古生物学者发现了古代企鹅的一个新品种
that lived some 57 million years ago and was the size of a refrigerator.
生于5.7亿年前，体积有冰箱那么大。
You heard that right, a refrigerator or like a tallest person.
是的你没听错，有冰箱那么大或是像最高的人一样。
Based on the size of the fossilized femur,
基于化石股骨的体积，
scientists estimate these giant penguins were 1.77 meters tall and about a hundred kilogram.
科学家预估这些巨型企鹅有1.77米高，约100公斤。
Researchers named the species Kumimanu biceae
研究员将这些物种称为Kumimanu biceae
based in part on the Maori words for bird and large mythological monster.
源于毛利语，鸟和大型神话怪物的意思。
Today the largest penguins are emperor penguins which are pretty big but they pale in comparison,
如今最大的企鹅是帝企鹅，虽然它们相当大，但和Kumimanu相比就相形见绌了，
they're full half metre shorter and less than half the weight.
相比之下，它们仅有Kumimanu的半米高且体重不及Kumimanu的一半。
But tens of millions of years ago, giant penguins were actually the norm.
但一亿年前，巨型企鹅实际上是标准体型。
Paleontologists know of at least nine other species dug up from places like Antarctica New Zealand and Peru.
古生物学者知道至少有9种其他物种发掘于新西兰南极局和秘鲁这样的地方。
This latest one isn't even the biggest, although that even taller bird height is based on just two bones.
这个最近发现的物种甚至不是最大的一个，虽然再重的鸟都仅靠两个骨头支撑。
The find was described in Nature Communications and includes vertebrae, wing and leg bones
研究结果发表于《自然通讯》杂志上，其中包含椎骨、翅膀以及小腿骨骼
and what stands out is that it's so old and different from other giant penguins.
引人注意的是其年代久远且和其他巨型企鹅不同。
A detailed comparison of the fossils puts this new bird on its own branch in the family tree
对化石的仔细对比将这种幸鸟类归于系谱图中的一支，
living at least 5 million years before most of the others
至少比其他物种早生500年
and that time gap suggests that penguins evolved gigantism more than once.
这种时间差表明企鹅不止一次进化成巨型企鹅。
Not only that but most paleontologists
不仅如此，大多数古生物学家
pegged the penguin origins story to the mass extinction 65 million years ago that killed the dinosaurs.
将企鹅起源故事和6500万年前杀死恐龙的大灭绝相联系。
That event eliminated the big, carnivorous reptiles in the ocean,
海洋中巨型食肉爬行动物在大灭绝中被淘汰，
creating an opportunity for seabirds that were divers rather than fliers.
为潜水的海鸟创造了机会。
The researchers guessed that once the birds didn't need to lift off anymore,
研究员猜测一旦鸟类不再需要起飞，
packing on weight might have been helpful for diving or competing for breeding grounds.
增重或许有助于潜水或争抢繁殖地。
But researchers hadn't expected such extreme sizes like Kumimanu,
但研究员不认为像Kumimanu这样巨大的体型
just ten million years after that ecological niche opened up.
会在生态位开启后的一亿年灭绝。
Even with that surprising suggestion,
即使有这样惊奇的猜测，
the bigger question might be why giant penguins aren't waddling around today.
大问题是为什么今天看不到摇摇摆摆的巨型企鹅。
The leading hypothesis is that marine mammals like whales and seals took over,
主要假设是，像鲸鱼和海豹这样的海洋哺乳动物接替了它们，
although scientists aren't clear on how that happened.
虽然科学家不清楚这是怎么发生的。
By the end of the Maya scene earth wasn't home to giant species anymore
玛雅情景式地球不再是巨型物种的家园
so the Penguins we know and love today are the smaller, cuddly or kind,
所以如今我们所知所爱的企鹅更小、可爱或友好，
I still wouldn't cuddle with an emperor penguin.
可是我还是拒绝和帝企鹅拥抱。
Thanks for watching this episode of scishow news.
感谢收看本期科学秀新闻。
If you like that second story
如果你喜欢第二个故事
and you want to learn more about ancient animals or all kinds of paleontological science,
并想要了解关于古代动物或古生物学科学知识，
you can check out our sister channel Eons at youtube.com/Eons.
你可以看看我们的姐妹频道youtube.com/Eons。
