A recent study shows that dinosaur biodiversity declined sharply in about 10 million years before an asteroid hit the Yucatan Peninsula in Mexico. According to researchers, the global cooling could be the reason for the decrease in the number and species of ancient animals.
According to a study published in June, a period of global cooling led to a sharp decline in the number of dinosaur species about 10 million years before their complete extinction caused by the fall of the asteroid.
The study, published in the journal Nature Communications, is the result of an international collaboration involving paleontologists from the University of Montpellier in France, the University of Bristol in the UK and the University of Alberta in Canada.
About 66 million years ago, an asteroid 12 km wide slammed into the Yucatan Peninsula in Mexico, initiating a “nuclear winter” that led to the extinction of the dinosaurs.
The research team focused on six families of dinosaurs, three carnivores and three herbivores, which survived 40 million years of evolution until the asteroid collided with Earth. They examined the fossils of over 1,600 individual dinosaurs, for a total of about 250 different species.
The results show that the biodiversity of the six families had already declined sharply in about 10 million years before the asteroid hit. The research results are significant as the decline in dinosaur biodiversity is observed worldwide in both herbivorous and carnivorous species.
Interestingly, the only family that showed only a slight decrease in biodiversity before the asteroid was the Troodontidae, a family of birdlike dinosaurs. Birds are known to be evolutionarily related to dinosaurs.
The researchers noted that herbivorous dinosaurs declined somewhat earlier than carnivores, making it very likely. It is likely that the decline in the number of herbivorous species was directly related to the decline in predators. This is an example of a cascading effect where extinction is caused by the extinction of another species in the ecosystem.
One of the theories explaining why the number of dinosaurs began to decline was climate change. During the Cretaceous period, between 145.5 and 65.5 million years ago, the Earth experienced a global cooling of 7-8 ° C.
Dinosaurs, which were mesothermal animals, meaning they needed a warm climate to maintain their body temperature and the functionality of their metabolism, were likely hit hard by this global cooling period.