Yangchuanosaurus spies on a group of Mamenchisaurus. - stock illustration

Some dinosaurs of the Dashanpu Formation of China near the Sichuan city of Zigong. The large 26 foot predator Yangchuanosaurus moves downstream and spies some large long necked sauropods called Mamenchisaurus. Moving among the feet of the large sauropods are stegosaurs called Gigantspinosaurus. Not unlike modern animals, the smaller plated herbivores eat low shrubs and plants and use the larger animals as lookouts and secondary protectors in a sort of symbiotic relationship. Though it is not known if dinosaurs really exhibit this behavior we can speculate.