But in this prehistoric world, giant carnivores with ultra-keen senses and powerful, razor-sharp weaponry are everywhere.
但在史前世界里，机敏凶猛的大型肉食动物几乎无处不在。
Throughout the Cretaceous, hungry carnivores patrol the landscape.
纵观整个白垩纪，饥饿的食肉动物游走在陆地上。
They are the most terrifying predators the world has ever known.
它们是史上最凶险的捕食者。
Their plant-eating prey, though, are well armed and well armored.
而它们的猎物，食草动物也全副武装。
They don't give in without a fight.
它们决不会轻易投降。
But prehistoric herbivores have a problem.
但史前食草动物有个软肋。
They lack the brainpower of the carnivores that hunt them.
它们不如那些追杀它们的食肉动物聪明。
Sauroposeidon's brain is so tiny, it can barely process any information at all.
波塞东龙的大脑如此之小，简直难以处理任何信息。
So just how did these intellectually challenged giants cope in such a dangerous world?
那么这些智力低下的庞然大物是如何在如此危险的环境下生存的呢？
There has to be some sort of device that compensated for this diminished capacity to make individual choice, and it's got to be society.
一定有些补救措施让它们能够作出个体反应，这就是群居。
Sauroposeidon defend themselves against super-predators by working and thinking together.
波塞东龙以群体思考和行动来抵御捕食者的攻击。
So you have group intelligence, group memory, group decision-making replacing individuality.
它们用群体的智慧，记忆以及群体决策替代个体。
Living as a group is vital for Sauroposeidon's survival. lndividually, their huge size is a powerful defense,
在群体中生活对于波塞东龙的生存至关重要。对于个体而言，庞大的身躯就是最佳防御，
but sticking together makes these Leviathans almost indestructible.
而聚集起来，这些庞然大物就变得坚不可摧。
Keeping a herd of 50-ton animals filled up, however, means traveling vast distances,
然而让重达五十吨的巨兽群填饱肚子意味着要走很远，
grazing a territory covering thousands of square kilometers.
通常要在上千平方公里的区域寻找食物。
And moving a mountain of flesh requires sophisticated coordination.
移动如此庞大的身躯要有极强的协调能力。
One of the curious things about sauropods is that they did have a swelling in the spinal cord, in the neighborhood of their pelvis.
蜥脚类恐龙的奇妙之处在于它们在骨盆附近的脊髓处有个突起。
It's sort of like a second brain help control the back half of the body
就像第二个大脑来控制后半部分身体，
It's called the sacro-lumbar expansion,
这叫做腰底扩张，
a bundle of nerves which acts like a primitive brain controlling the movements of the back legs and tail.
一组神经发挥简易大脑的作用，控制着后腿和尾部的活动。
The brain in Sauroposeidon's head is simply too small and far away to coordinate its front and back legs.
波塞东龙头部的大脑太小，距离后腿又远，很难控制后半部分身体。
So a second brain operates at the back of the animal.
所以其后半部分由第二个大脑来操控。
