侏罗纪搏击俱乐部 第75期:鲸其实是有腿的

 　　Incredibly, whales are closely related to hoofed 1 animals, in particular, the pig and the hippo.

　　很难相信，鲸类跟有蹄类动物的关系非常接近，特别是，猪和河马。
　　55 million years, the actual evolutionary 2 origins of whales and which group of land animals they're most closely related to has been the subject of a lot of interest in recent years.
　　五千五百万年来，鲸实际的进化起源以及它们与哪种陆地动物最亲近，是近些年来吸引了很多兴趣的话题。
　　And, the paleontological evidence, the fossil evidence and evidence from looking at the DNA 3 of living whales and other animals now really strongly points to whales being very closely related to hoofed mammals.
　　古生物学证据、化石证据以及对现代鲸类和其它动物DNA的研究结果现在真的有力地指向鲸类与有蹄类动物的亲缘关系非常接近。
　　We actually have found hind 4 legs of walking whales.
　　我们确实找到了陆行鲸的后腿。
　　And the hind leg has what we call a double-trochleated astragalus.
　　其后腿上有我们称作双滑轮结构的距骨。
　　And this is an astragalus or an ankle bone, which has a both an upper and lower curved surface which allows the spring in the step.
　　这就是一块距骨或者说踝骨，其表面同时有向上和向下的弯曲，使之在走路时有弹性。
　　It allows a deer to jump a fence.
　　这使得鹿能越过栅栏。
　　And these earliest whales, which are walking whales, have that kind of hind leg.
　　这些最早的鲸，做陆行鲸，就有那样的后腿。
　　No other kind of mammal has that kind of hind leg.
　　没有其他的哺乳动物有那样的后腿。
　　But unlike the mega shark, the biting sperm 5 whale lived in families called pods.
　　不过与巨型鲨鱼不同的是，噬抹香鲸以家族为单位成群生活。
　　Whales in general are social animals and sperm whales are too, they go in small groups.
　　鲸一般是社会性动物，抹香鲸也是，它们小群活动。
　　And, we would expect that, back in the Miocene, there were little pods of sperm whales, and we might also suppose that if they came under attack they might try to help defend each other.
　　我们可以想象，在第三纪中新世，抹香鲸就这样小群活动，而且我们也能推测如果它们受到攻击它们会帮助保护彼此。
　　There's huge advantages of hunting as a pod or as a group because you can do things as a group that you can't do as an individual.
　　小群或者成组狩猎能带来很大的好处，因为组群能完成个体没法做到的事情。
　　You can herd 6 prey 7, you can attack from multiple sides.
　　能够围赶猎物，能从多个方向发动攻击。
　　So I think, given the opportunity, they almost certainly would hunt in pods.
　　所以我想，要是有机会，它们大概一定会成群狩猎。
　　Working together in a pack, allowed the biting whales to be more successful hunters.
　　在鲸群里一起合作，使得噬抹香鲸成为更成功的猎手。
　　But becoming separated from the group could spell disaster.
　　不过要是跟鲸群分开就可能会是灾难。
　　Living in a pod and having such a massive body made them lethal 8, but its name, the biting whale, describes its true source of power, the teeth.
　　成群生活加上那样一个庞大的身躯使它们危害极大，不过它的名字噬抹香鲸，描述了它威力的真实来源，牙齿。
　　What makes Brygmophyseter such an incredible whale is that it's got both upper and lower teeth, you look in that mouth, there's 44 teeth in there.
　　让四贺鲸成为如此奇鲸的原因是它上下颌上都有牙齿，你看看那张嘴里面，有44颗牙齿。
　　Now they're not the teeth of a cute loveable whale.
　　它们可不是可爱的小鲸的牙齿。
　　They are the same size as the teeth that you'd see in the mouth of Tyrannosaurus Rex.
　　它们的大小和在霸王龙雷克斯暴龙嘴里的一样。
　　They have large teeth.
　　它们有巨大的牙齿。
　　The teeth aren't wickedly serrated like teeth from the Megalodon or some of the other big sharks. But they're large blunt, kind of peg 9 like teeth.
　　这些牙不像巨齿鲨或其它巨鲨的牙齿那样有狡黠的锯齿。而是又大又钝、像桩子一样的牙齿。
　　The teeth are interlocking, in fact, this tooth which I have of a related sperm whale shows where the opposite tooth came right down here and occluded 10 against this crown.
　　这些牙齿上下交错，事实上，我这颗是它抹香鲸亲戚的牙齿，能看出来对面牙齿直接下来到这里堵住这个牙冠。
　　And this is very typical of these fossilized teeth.
　　这是这些牙齿化石非常典型的特征。