We’ve long known that human actions—cutting down forests, building cities and using up natural resources—puts animals in danger, and can even drive them out of existence. Now, a new study has found that vertebrates—or creatures with a backbone—are dying much, much faster than they should be.
A group of researches from Mexico and the US wanted to compare the rate of extinctions in the last century to what is known as the “background rate”—the rate at which species have died off in previous centuries. They found that vertebrates, or animals with a backbone, were dying at a rate 114 times faster than the overall background rate for vertebrates, based on a conservative estimate.
The news was especially grim for the adorable lemur, which may be one of the next vertebrate species to go extinct.
The research was published June 19 in the journal Science Advances. Scientists at the Universidad Nacional Autónoma de México, as well as eminent universities in the US including Stanford, Berkeley, Princeton, and Gainesville, Florida, contributed to the study.
Using the background rate as a guide, researchers said that only nine vertebrate extinctions should have occurred since 1900. In fact, 477 vertebrates became extinct during that time period, including 69 mammal species, 80 bird species, 24 reptiles, 146 amphibians, and 158 fish.
“These estimates reveal an exceptionally rapid loss of biodiversity over the last few centuries, indicating that a sixth mass extinction is already under way,” the paper states.
And those are the conservative estimates. “Our calculations very likely underestimate the severity of the extinction crisis,” noted study co-author Professor Paul Ehrlich. “There are examples of species all over the world that are essentially the walking dead.”
While the most famous mass extinction phase is the one which many scientists believe killed off the dinosaurs, there are five known extinction phases that predate it, including the Great Dying 248 million years ago in which 96% of species perished. The dinosaurs were finally finished off by an asteroid about 65 million years ago.