Remember the mass-extinction event that wiped out the dinosaurs? Earth is apparently on the verge of another great biological extinction, and humans are solely to blame.

Scientists have previously classified five large-scale losses of animal life as mass-extinction events, all of which occurred millions of years ago. In recent years, the planet has seen the loss of hundreds of species of animals, and according to a new analysis from an international team, the planet may be in the early days of its sixth mass-extinction event.

As part of the study, researchers analyzed previous studies and scientific data to draw their conclusion that human activities and population surges worldwide -- not a catastrophic event, like an asteroid impact, for example -- are responsible for the drastic decline of animal life. Lead author Rodolfo Dirzo, a biology professor at Stanford University, cites actions like overexploitation of resources and habitat destruction as examples of harmful human activities.