Don, you sure are lucky don't have to give birth.
唐，你很幸運不用生孩子。
I'm glad we're an intelligent species, but boy, thatinfant head feelsmighty large going through thatnarrow birth canal.
我很高興人類有著聰明才智，但是天啊，嬰兒的腦袋要從狹窄的產(chǎn)道出來，那是很痛苦的。
And then,after all that, the baby comes out facingdown and backwards,which means you're helpless toassist it, or even to untangle itfrom the umbilicalcord.
而且，經(jīng)歷過這一切后，寶寶出來是面向下和倒過來的，你根本沒辦法協(xié)助它，或者甚至不能幫忙解開臍帶。
Well, Yeal. According to evolutionary anthropologists, babies of the earliest humans had afifty-fifty chance of coming out facing backwards.
是的，雅埃爾。根據(jù)人類進化學(xué)家，人類早期時候的嬰兒生出來是有二分之一的可能性是面向后面的。
This was a result of humans learning to walk on two feet.
這是人類學(xué)習(xí)用兩只腳走路的結(jié)果。
As the pelvis became optimized for walking, the birth canal developed twists and turns thatmeant the baby had to rotate in order to keep its head and shoulders aligned with thewidestpart at all times.
隨著盆骨越來越適應(yīng)走路，產(chǎn)道就變得迂回曲折，嬰兒就得旋轉(zhuǎn)過來保持它的頭和肩膀總是與最寬的部分在同一平面上。
And then our brains also got bigger.
然后頭也會變得更大。
Which meant more twists and turns.
也意味著更多的扭轉(zhuǎn)。
And backwards-facing babies, stupid,huh?
唐，你很幸運不用生孩子。
I'm glad we're an intelligent species, but boy, thatinfant head feelsmighty large going through thatnarrow birth canal.
我很高興人類有著聰明才智，但是天啊，嬰兒的腦袋要從狹窄的產(chǎn)道出來，那是很痛苦的。
And then,after all that, the baby comes out facingdown and backwards,which means you're helpless toassist it, or even to untangle itfrom the umbilicalcord.
而且，經(jīng)歷過這一切后，寶寶出來是面向下和倒過來的，你根本沒辦法協(xié)助它，或者甚至不能幫忙解開臍帶。
Well, Yeal. According to evolutionary anthropologists, babies of the earliest humans had afifty-fifty chance of coming out facing backwards.
是的，雅埃爾。根據(jù)人類進化學(xué)家，人類早期時候的嬰兒生出來是有二分之一的可能性是面向后面的。
This was a result of humans learning to walk on two feet.
這是人類學(xué)習(xí)用兩只腳走路的結(jié)果。
As the pelvis became optimized for walking, the birth canal developed twists and turns thatmeant the baby had to rotate in order to keep its head and shoulders aligned with thewidestpart at all times.
隨著盆骨越來越適應(yīng)走路，產(chǎn)道就變得迂回曲折，嬰兒就得旋轉(zhuǎn)過來保持它的頭和肩膀總是與最寬的部分在同一平面上。
And then our brains also got bigger.
然后頭也會變得更大。
Which meant more twists and turns.
也意味著更多的扭轉(zhuǎn)。
And backwards-facing babies, stupid,huh?