Hu, Y, Meng, j., Wang, Y. and Li, C. (2005) Large Mesozoic mammals fed on young dinosaurs Nature 433, 149 - 152

The thought that all mammals were small creatures during the Mesozoic is not correct. Two years ago in China\\\\\\\'s Liaoning Province (Yixian Formation) villagers discovered the remains af a Mesozoic dog sized mammal called Repenomamus robustus known previously from skull fragments Its stomach contents revealed the remains of a juvenile Psittacosaurus. The discovery constitute the first direct evidence that some triconodont mammals were carnivorous and fed on small vertebrates, including young dinosaur. Mesozoic mammals possible occupied diverse niches and some large mammals probably competed with dinosaurs for food and territory. A nearly as big Mesozoic triconodont mammal called Gobiconodon schaffi is knwon from EC Cloverly Formation (US) and another not yet described Mesozoic mammal may even turn out to be bigger.