For egg-laying animals, it's almost always in the late spring or summer.
对卵生动物来说，一般都会在晚春或是夏季进行繁殖。
That way, the eggs can be incubating during the summer, during the warmest part of the year,
那样的话，蛋就能在夏季里孵化，也就是一年中最温暖的季节，
when the climate is the most amenable to the production of young.
那时气候宜人，是最适合哺育幼崽的季节。
To know when to mate, dinosaurs react to the change of seasons.
为得知何时将会交配，恐龙会对季节的变化做出反应。
In the weeks leading up to the breeding season,
在繁殖季节的前几周内，
there would be hormonal changes taking place in the body of the dinosaur that are triggered by passing time itself...
恐龙体内的荷尔蒙会发生一定的变化，并且是随着时间变化而变化的，
by the length of the day, for example.
比如说，由白昼的长短来决定。
As winter recedes, the days get longer.
随着冬天的逝去，白天会变得更长。

Sensors in the back of the eyes respond to changing light, transmitting crucial information to the brain.
位于眼睛后方的感光器官会对光线的变化做出反应，并把重要讯息传递给大脑。
A signal triggers the pituitary gland to release the hormone gonadotropin.
这个信号会促使脑垂体释放出促性腺激素。
These chemicals prepare their bodies to produce eggs or sperm.
这些化学物质会让身体准备好产生卵子或精子。
Raging hormones also trigger dramatic changes in behavior, and very different changes in males and females.
激增的荷尔蒙也会使它们的行为发生巨大的变化，而且雄性和雌性的变化大相径庭。
For the females, that means stockpiling resources to produce the offspring.
对雌性来说，它们会囤积营养为产卵最好准备。
For the males, that means figuring out how they're gonna beat the other males at the game of reproduction itself.
而雄性，则会一直思考着如何才能在这场繁殖大战中打败其他的雄性竞争者。
They're more alert. They're more visual. They're being more aggressive.
它们会更警觉。眼神会更好，也更具侵略性。
There are more fights, beginning a whole cascade of social complexity which would be really fun to watch.
那时会有更多的战斗，并会创建一连串复杂的社会关系，那看上去将会很有趣。
With hormones racing through their veins, a carnivore's advanced killing tools become even more deadly.
随着荷尔蒙在血液里的激增，食肉动物先进的杀戮武器会变得更加致命。
Between the ages of 15 and 18, the mortality rate for meat eaters like T. Rex increases five-times.
在十五至十八岁之间，像雷克斯霸王龙这样的食肉动物，其死亡率较平时会增加五倍。
This is the age adolescent males begin to challenge older, more experienced males.
在这个年龄段里年少的雄性恐龙会开始挑战更年长，更富经验的雄性恐龙。
Battles may start over a mate, but they can quickly develop into a death match.
开始可能只是为了争夺配偶而战，但很快这将会演变成一场生死之战。
There's going to be some threshold, some test that the male has to pass to get the privilege of mating with the female, get the privilege of reproducing.
雄性恐龙必须要通过一些门槛和测试后才能获得与雌性交配的特权，和繁殖后代的特权。
Fights break out over territory, bravado, and, of course, to impress females.
战斗通常因领地而起，有时也是虚张声势，当然也为了博得雌性的好感。
These clashes are shows of strength meant to prove who has the best genes.
这些冲突都是力量的展现，意在证明谁的基因才是最优秀的。
Fortunately, most of the time, the aim is not to kill your opponent.
幸运的是，在大部分情况下它们都不想置对手于死地。