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Thanks to Skillshare for supporting this episode of SciShow.
感谢Skillshare对本期《科学秀》的赞助。
Most kinds of babies are pretty cute.
大部分物种的宝宝都超级可爱。
But when you compare a day-old kitten to a day-old deer, there are some clear differences.
但当你把刚出生一天猫猫和刚出生一天的鹿相比，你会发现其中有一些明显的差别。
The kitten can't open its eyes, while the deer can walk.
小猫连眼睛都睁不开，小鹿就已经会走路了。
Why did nature give us some animals babies that are almost totally helpless,
为什么大自然会赋予我们这些几乎完全弱小无助的动物宝宝
while other animals have babies that walk, hop, or run just hours after birth?
而其他动物的宝宝出生几个小时后就会走路或者跑跑跳跳呢？
There are advantages and disadvantages to both reproductive strategies. Take hares and rabbits, for example.
两种繁殖策略各有优劣。例如野兔和家兔。
They're similar animals, but baby rabbits are altricial, meaning they're born helpless, and require a ton of parental care.
它们是类似的动物，但是家兔的宝宝是晚熟动物，这意味着它们一出生就就很无助且需要大量的亲代抚育。
Their eyes are closed, they lack fur, and they can't regulate their own body temperature.
它们的眼睛紧闭，没有皮毛，它们也无法调控自己的体温。
Hares, on the other hand, are precocial, meaning they're born more developed.
而野兔是早熟动物，意味着它们生来发育就更成熟。
Their newborns have fur, and their eyes are open. These terms are typically applied to mammals and birds,
它们的宝宝有皮毛，眼睛也是睁开的。这些特性通常也适用于哺乳动物和鸟类，
where we can observe clear differences in the relative helplessness of their babies, like the kitten and the deer.
我们可以在它们身上清楚的看到它们宝宝相对无助性的差别，比如小猫和小鹿。
Both groups are known for parental care, as well.
两组动物都是亲代抚育型。
In altricial species, in particular, parental care is a huge commitment.
尤其是在晚熟物种中，亲代抚育是一个巨大的承诺。
They spend a large amount of time investing in their offspring,
和早熟物种父母相比，
compared to parents of precocial species - things like preparing nests or caring for their babies.
它们花大量的时间投资自己的后代，比如准备巢穴和照顾它们的宝宝。
And animals that are more helpless at birth are extra vulnerable when they encounter a predator.
刚出生时比较无助的动物，在遇到捕食者时就会格外脆弱。
But the parent also spends less time incubating the offspring before they're born and hatched,
但在宝宝出生和孵化之前，父母花在孵化孩子上的时间也更少，
and as a result, altricial animals may be able to produce larger, more frequent litters.
因此，晚熟动物可能能够生出更大的幼崽。
But while the parental investment required of these animals is enormous, it may also be relatively short-lived.
但虽然这些动物所需的父母投入巨大，但或许也是相对短暂的。
Altricial birds, for example, require a lot of care in the beginning,
例如晚熟鸟类一开始需要大量的抚育，
but they mature more rapidly and become independent more quickly than precocial birds.
但它们比早熟鸟类成熟得更快，独立得更快。
Many precocial animals take longer to develop before birth, and parents usually give birth to only one or a few babies.
很多早熟动物在出生前需要更长的时间来发育，父母们通常只生一只或几只宝宝。
That's fewer offspring available to pass on the parents' genes,
和晚熟物种相比，这使得能够传递父母基因的后代更少了，
compared to altricial species, at least if those bigger litters survive.
至少如果那些更大的幼崽存活下来的话。
And some precocial babies, like certain species of bird, still receive food from their parents,
一些早熟动物，比如某种鸟类，仍然从父母那里获取食物，
even though they're capable of leaving the nest on their own. Meaning they still need some parental care.
即便它们已经能够自己离开巢穴。这意味着它们仍需要一些亲代抚育。
But, there are also advantages to being precocial.
但早熟也有优势。
Because precocial babies are well-developed, they require less parental care overall.
因为早熟宝宝发育很好，它们整体所需的亲代抚育就更少。
Their parents still invest in them, since it takes more energy to incubate more developed babies.
它们的父母仍给它们投入，因为培育更成熟的宝宝需要更多的能量。
But once they're born, the kids are more independent.
但它们一旦出生，宝宝们就更加独立。
When confronted by a predator, a precocial baby has a better chance of survival than an altricial baby.
在面对捕食者时，早熟宝宝生存的几率比晚熟宝宝更高。
Some precocial babies, like the blue wildebeest, can even outrun predators within a day of birth.
一些早熟宝宝，比如蓝非洲野羚，甚至在出生后的一天内就能逃脱捕食者。
So each strategy has its advantages, and not all birds and mammals fit neatly into one group or the other.
所以每种策略都有其优势，并不是所有鸟类和哺乳动物都能准确的归为哪一组。
Like humans, for example: our offspring incubate for a long time, but they're still super helpless.
例如人类：我们的后代在经历长时间的养育后，仍然超级无助。
The precocial or altricial question is a spectrum, with babies born at varying stages of development, and parents providing varying degrees of care.
早熟还是晚熟只是一个范围，宝宝在不同发育阶段出生，父母们就提供不同程度的照顾。
How helpless a baby is, and how much care its parents provide
宝宝有多么无助以及父母需要提供多少照顾
depends a lot on the species' own individual adaptations given its environment and circumstances.
很大程度上取决于特定环境和环境下物种自身的适应性。
And that can influence how developed the babies of each species will be.
并且这会影响到每个物种后代的发育。
What works for the rabbit may not necessarily work for the hare, and vice versa.
适合家兔的不一定适合野兔，反之亦然。
If you love baby animals of all kinds, altricial or precocial, you might like to immortalize them in photographs.
如果你喜欢各种动物宝宝，不管是晚熟还是早熟的，你或许会喜欢给它们拍照。
Which is why the photography courses at Skillshare can come in handy.
因此给大家推荐Skillshare的摄影课程。
Skillshare is a creative online learning community.
Skillshare是一个创造性的线上学习社区。
They offer literally thousands of courses in everything from business to design.
他们提供从商业到设计的数千门课程。
In his class on Outdoor Photography, Chris Burkard teaches you how to get the perfect shot at every time of day.
在Outdoor Photography的课堂上，Chris Burkard会教你怎么在每天的每个时刻拍出最好的照片。
From lighting to landscapes, it's all there. Premium subscribers get access to every single course on Skillshare,
从灯光到取景，应有尽有。付费用户可观看每个课程，
from productivity to illustration, and you can get an annual subscription for less than $10 a month.
从生产到插图，你还可以以每月不到10美元的价格获得年度订阅。
The first 500 SciShow subscribers to use the link in the description will get a 2-month free trial.
前500名使用下方链接注册的观众可获得两个月的免费试用。
So you can take all those courses for a test drive and see which of them are right for you!
你可以参加所有这些课程，看看哪些适合你！
