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。
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 .
窃蛋龙