Toefl writing essay The main discussion is whether the R.robustus mammals were an active hunters or they were just a scavenger. According to the passage, the R.robustus were too small to hunt a psittacosaurus. One of which was found in one of the R.robustus stomach. However, the lecture explains that even though there is a huge size differences between the R.robustus to the dinosaur, perhaps the psittacosaurus unhatched eggs had been eaten by the R.robustus. In addition, the passage describes that R.robustus legs are way too short to chase dinosaurs. On the other hand, the lecture gives an explanation. Nowadays It is very common that modern mammals have short legs similar to R.robustus. As a result, modern mammals were actually faster than their prays and against all odds succeed to hunt them. To sum things up, If modern mammals similar to R.robustus were predators, we can now imagine ancient mammals as predators as well. Furthermore, the dinosaurs that was found in the R.robustus stomach had no teeth marks on their bones, which could supply a terrific evidence. However, the lecture gives an answer for that. When the R.robustus hunted, it did not use their teeth but use their big jaws in order to swallow the whole or big pieces of the dinosaur.