题目：The feeding ecology of the predatory theropod dinosaurs
主要内容：Longstanding views on the extinct non-avian theropods are that these were often highly specialised carnivores. Dromaeosaurs for example have been considered the ultimate killing machines whereas derived tyrannosaurs have been suggested to have been obligate scavengers, and large theropods in general are typically identified as predators of adult dinosaurs. In this work I present new evidence for scavenging in dromaeosaurs and tyrannosaurs, based on tooth-marked bones and shed teeth, which suggests that at both ends of the carnivore-predator spectrum, theropods would do both. Furthermore a detailed assessment and review of the available evidence of large theropod predatory behaviour suggests that they preferred juvenile prey and did not target adults. This is supported by evidence from coprolites, gut contents, the rarity of juvenile dinosaurs in the fossil record and closely matches the known behaviours of extant predators. In conclusion, theropod dinosaurs showed a wide variety of adaptaive behaviours and it is likely that all groups engaged opportunistically in both predation and scavenging on occasion. Moreover, the pruning of juvenile dinosaurs from the fossil record by theropods may have a profound impact on how we view dinosaur ecosystems and the population ecology of dinosaurs.