Why didn’t the small post apocalypse survivor dinosaurs just refill the niches? Did the asteroid alter the planet in some way fundamentally different than the prior 200M years?
Edit: (collaborative clarification with my 5yo, with paraphrasing): Birds are boring dinosaurs. Why didn’t the big dinosaurs (non bird) come back? Why are there no mammal-sized (non bird) dinosaurs? (e.g., mouse through elephant-sized or even whale size)
In: 77
One leading theory is that reptiles are poorly adapted to dealing with fungal infections. Fungi don’t handle high temperatures very well: warm-bloodedness comes with many advantages but one important one could be the difficulty it causes for fungi to infect our bodies. As some evidence, scientists analyzed the energy cost to maintaining a higher body temperature and calculated the best cost-to-benefit temperature and found it to be… 98.6°F!
Not all dinosaurs were *cold* blooded. Some of them may have been mesothermic, and some may have actually been warm-blooded. However, in general they weren’t adapted to have the kind of high body temperature necessary to prevent fungal infections.
Post-asteroid was the perfect environment for fungi to thrive: it was dark, cool but not cold, and *covered* in dead, decaying organic material. That greatly increased the risk of fungal infections. The warm-blooded mammals had the advantage, being less likely to get infected.
Likely there were many factors, but that **may** have been a significant reason for why mammals were able to replace the dinosaurs.
Latest Answers