评论
打印
So researchers have wondered about the evolution of male parenting behavior in birds for quite some time.
研究者一直都很好奇，鸟类的雄性育儿行为都是怎样进化而来的。
And now there's research showing that for some of the birds' dinosaur relatives, it's likely that the male parent was also in charge of taking care of the eggs.
现在有研究证明，对鸟类的一些恐龙亲戚来说，很可能是父方负责照料恐龙蛋。
How did they figure that out?
他们怎么发现的？
Well, first they looked at clutch volume, that's the number of eggs in the nest of crocodiles, birds and three types of dinosaurs, including Oviraptors that are thought to be closely related to the dinosaur ancestors of birds.
首先他们从产卵数入手，也就是鳄鱼、鸟类和三种被认为与鸟类的恐龙祖先关系非常密切的恐龙（包括窃蛋龙）窝里有多少蛋。
So when researchers examined fossilized remains of nests, they found that the dinosaurs had larger clutch volumes, more eggs in the nests that is, than most of the crocodiles and birds that were studied.
当研究人员检验这些窝巢里的化石遗迹时，他们发现恐龙的产卵数更大，也就是说，在窝里有更多的蛋，比研究内大多数鳄鱼和鸟类都多。
But, and this is important, their clutch volumes matched those of birds that have only male parental care.
但（这点很重要）它们的产卵数和鸟类中只有父方抚养幼儿的数量是吻合的。
You see, bird species in which only the males take care of the nest tend to have the largest clutches of eggs.
鸟类中，只有父方照顾幼儿的鸟往往有最多的蛋。
So what's the connection between bird and dinosaur behavior?
那么，鸟类和恐龙的行为之间有什么联系呢？
Well, researchers now believe, because of this study, that the male parenting behavior of these birds might have its origins in the behavior of dinosaurs.
由于这个研究，研究人员现在相信，鸟类中的父方育儿行为可能源自恐龙行为。
Based only on evidence of clutch volume size, the number of eggs?
证据只有产卵数吗，即蛋的数量？
No, there's more.
还有更多证据。
They also examined the fossilized bones of those three types of dinosaurs that were found on or near nests to determine their sex.
他们还检验了这三种在窝巢上或旁边发现的恐龙化石，来确定恐龙性别。
You see, adult female birds during egg production produce a layer of spongy bone tissue inside certain long bones.
成年的雌鸟在产卵时会在某些长骨中分泌一层海绵状的骨组织。
And so did female dinosaurs of the kinds that were investigated.
所调查的雌雄恐龙中也是这样的。
This spongy tissue serves as a source of calcium for eggshell formation.
这层海绵组织是为蛋壳的形成提供钙质的。
But when the dinosaur fossils were examined, there were no spongy bone deposits, meaning that those dinosaurs on the nests were probably adult males who wouldn't have needed calcium for making eggshells.
但人们在检验恐龙化石时，没有发现任何海绵骨沉淀。也就是说，这些在窝里的恐龙很可能是成年雄性恐龙，它们不需要形成蛋壳所需的钙质。
Exactly. And then there's this: birds like the kiwi, the ostrich and the emu; they share certain physical characteristics with these dinosaurs.
正确。还有：像几维鸟、鸵鸟和鸸鹋鸟的这些鸟类，与这些恐龙有着相同的生理特征。
And interestingly, they also show a consistent pattern of nest care by the male.
有趣的是，它们也表现出一贯的父方育儿的模式。
