CustardFist

There's a newish hypothesis that the reason mammals rose to power after the asteroid killed most dinosaurs was because the fungal spread that followed the impact due to the ash-filled sky and sudden rise in dead plant and animal material would have led to a huge rise in fungal infections, which are far more severe in cold-blooded animals than warm-blooded ones, allowing mammals to live longer and have more offspring than reptiles in spite of the fact that reptiles would otherwise be far more suited to survive in a food-scarce world.