Why Mammals Replaced Dinosaurs

Everyone knows that about 69 million years ago a cataclysmic event occurred that caused the extinction of most dinosaurs. The cause is still debated, but the most likely cause at present is the impact of a large asteroid on what is now the Yucatan Peninsula.

But whatever happened, the result is unquestionable: the age of the dinosaurs is over and mammals have taken their place. But here I would like to ask why mammals and not insects, as in the Mesozoic, for example? What advantages did our ancestors have?

po vyhynutí většiny dinosaurů nastaly velké změny

First of all, they were warm-blooded animals, and with that the ability to regulate their body temperature. This was aided by their fur, which was more insulating than the dinosaurs\’ primitive feathers. Because of their small size at the time, they did not need much food, and because they were omnivorous, they could eat whatever was at hand, or even on their paws.

The main reason for their success, however, was that they did not lay eggs and carried out the development of their young inside the mother\’s body. This greatly increased their chances of survival, as the eggs were no longer in danger of being eaten by predators or the embryos dying in bad weather. These are, after all, the things that help mammals to this day.

první savci se podobali dnešním hlodavcům

So it is understandable that when living space became available after the mass extinction, mammals quickly filled it. Of course, there were insects as well, but we must not forget that the oxygen content of the atmosphere was not so high at that time that the terrestrial invertebrate community could not reach such a size.

Of course, not all dinosaurs perished. While some species survived, they were generally smaller, more adaptable types. And now that truly large predators no longer existed, or at least were few and far between, mammals had a clear path to success.

Not surprisingly, it did not take long for mammals to grow into a wide variety of genera and species, gradually filling various ecological niches. And here we are today. Of course, one wonders how long this successful journey will continue and who will succeed them.