 He also argued that the shallow footprints, the positioning of the nares and the loss of functioning forelimbs in theropods can be explained only through aquatic evolution.Critics showed that the idea had been rejected in previous decades.In 2018, he furthered this theory by suggesting that the hypothetically aquatic non-avian dinosaurs would have reproduced in lakes, and went extinct not because of an asteroid impact, but due to the disappearance of their "sex lakes", publishing his findings in his book, "Too Big to Walk