I can’t resist a good dinosaur story and so, though this isn’t a new one, I’m going to run with it. A paper published last summer in the Journal of Evolutionary Biology speculated on just how harsh life was after the meteor impact 66 million years ago. We all know that that was the end of the dinosaurs but all other forms of life were also catastrophically curtailed.
The big losers were the non-avian dinosaurs. T-rex, triceratops, brontosaurus; all gone. In fact, all land animals larger than a good sized domestic cat were wiped out; including mammals. The general picture is that, as dinosaurs died, this left the world wide open to colonisation by the mammals. Whilst this is true, the story is more complex and it was by no means inevitable that the mammals would rise to be the dominant class on land. The analysis by researchers at the University of Bath, UK, says that 93% of all known mammalian species on the north American continent went extinct along with the dinosaurs; only 4 were left.
Whilst the coprolite had really hit the fan the team also revealed that nature bounced back strongly and quickly. In an evolutionarily short 300,000 years the biodiversity of fauna had become twice that before the impact, that’s quick. It makes sense, though. Yes, it was literally hell on earth; a large part of the earth had been vaporised; but, if you were small, comfortable in the dark of the nuclear winter and not a fussy eater then there was a big, broadly empty planet out there for you to take advantage of. That’s a lot of little niches to fill.
Mammals and dinosaurs had coexisted for over 100 million years before Chicxulub became the world’s most famous crater, but with all the predators suddenly gone small, insectivorous mammals became lord of the manor. The result: we now have over 5,000 mammal species to wipe out at our leisure as we take up ever more of the planet’s dwindling wild spaces. It is now fairly well accepted that the archaeologists of the future will easily make out the dawn of the Industrial Revolution in the strata of the earth. How that story ends is up to us and how we react over the next century. Hopefully those archaeologists will not only know about the mammals that ruled the earth up until the anthropocene era through their history lessons.