More has been published about the extinction of dinosaurs at the K-T boundary than any other group of organisms. Excluding a few controversial claims, it is agreed that all non-avian dinosaurs went extinct at the K-T boundary. The dinosaur fossil record has been interpreted to show both a decline in diversity and no decline in diversity during the last few million years of the Cretaceous, and it may be that the quality of the dinosaur fossil record is simply not good enough to permit researchers to distinguish between the choices.[54] Since there is no evidence that late Maastrichtian nonavian dinosaurs could burrow, swim or dive, they were unable to shelter themselves from the worst parts of any environmental stress that occurred at the K-T boundary. It is possible that small dinosaurs (other than birds) did survive, but they would have been deprived of food as both herbivorous dinosaurs would have found plant material scarce, and carnivores would have quickly found prey to be in short supply.[35] The growing consensus about the endothermy of dinosaurs (see dinosaur physiology) helps to understand their full extinction in contrast with their close relatives, the crocodilians. Cold-blooded crocodiles have very limited needs of food (they can survive several months without eating) while warm-blooded animals of similar size need much more food in order to sustain their faster metabolism. Thus, under the circumstancies of food chain disruption above mentioned, non-avian dinosaurs died [55] while some crocodiles survived. In this context, the survival of other endothermic animals, such as some birds and mammals, could be due, among other