Mammoths, mastodons and other ancestors of modern elephants have been decimated by climate change even before the spears of prehistoric hunters: a parable similar to that of dinosaurs, already in sharp decline due to the climate in the 10 million years before the fall of the asteroid.
This is indicated by two international studies published respectively in Nature Ecology and Evolution and Nature Communications.
The first study, conducted by paleontologists from the universities of Bristol (Great Britain), Alcalà (Spain) and Helsinki (Finland), examined the remains of ancient proboscidia preserved in museums around the world to reconstruct the evolution of 185 species in 'span of 60 million years. By analyzing traits such as the size, shape of the skull and the chewing surface of the teeth, the researchers found that the evolution of these animals accelerated dramatically 20 million years ago, when they left Africa to migrate to Europe. Asia and North America. The risk of extinction peaked 2.4 million years ago in Africa, 160,000 years ago in Eurasia and 75,000 years ago in America:a timing that reflects that of climate change and not the expansion of early human populations or the development of tools for hunting large herbivores.
The climate would also be responsible for the decline of dinosaurs, as evidenced by the second study conducted by the universities of Bristol and Montpellier. "We studied the six most widespread dinosaur families in the Cretaceous, between 150 and 66 million years ago - explains the first author Fabien Condamine - and we observed that they were successfully evolving and expanding until 76 million years ago, there was a sudden decline. The extinction rate has risen and in some cases the rate of emergence of new species has plummeted ”. Two factors led to this upheaval: "the first is that the climate has become colder, making life difficult for dinosaurs - explains Mike Benton of Bristol - then the loss of herbivores, which has made ecosystems unstable and susceptible to a cascade of extinctions ".
