侏罗纪的晚期自1亿6000万年前开始，地球上的大部分被森林覆盖，由于气候逐渐变得暖和、潮湿，食草龙已经发展到80吨左右的巨大体型。在溪流浅水处，一群角鼻龙已经成功的将一只带着小恐龙的食草龙分离出来，其它食草龙则在拼命逃跑。最右边这只较小的捕食者（Ornitholestes）也被驱逐了。勇敢的母亲已经用后退站立了起来，时刻准备用庞大的身躯踩踏敢入雷池者！ This scene depicts an attack played out in a shallow stream-bed with forested banks, about 140 million years ago in the area that is now Utah, Colorado, and Wyoming. An attacking group of ceratosaurs has isolated an individual camptosaur, in the foreground, as well as a mother and juvenile barosaur, in the background, while the other barosaurs and camptosaurs flee. Also fleeing in the right foreground is a smaller predator, Ornitholestes.(words from amnh.org)