65 million years ago, dinosaurs and other creatures were wiped out in a mass extinction. Now, a new study by paleobiologist Anthony Barnosky of the University of California, Berkely predicts that three-quarters of today’s animal species could disappear within 300 years. Barnosky and colleagues used fossil records to calculate the death rate of mammals during the past 65 million years. On average, they found that the extinction rate was less than two species per million years; in the past 500 years though, a minimum of 80 to 5570 species of mammals have gone extinct. This is well above the rate of mass extinction, which is defined as a quick disappearance of three-quarters of all species. When current endangered or threatened mammals are added to these numbers, the rates predict that 334 years from now, 75% of all mammal species will be gone. Extending the same analysis method to amphibians, reptiles, birds, plants, mollusks, and other forms of life results in similar outcomes. In general, about 1% to 2% of all species are already extinct today, and about 20% to 50% are threatened. “Our best guess is that the current extinction rate is between three to 80 times too high,” states Barnosky, “Assuming threatened species would actually go extinct…puts the extinction rate off the charts.” This rate however, is not inevitable. Barnosky also claims that if humans actively work to protect endangered species and their habitats, the mass extinction could be prevented, or at least delayed, by thousands of years.