In what could be a huge new breakthrough in our understanding of dinosaurs, a pair of scientists are claiming in a new research paper that dinosaurs may have been on the way out the door before the asteroid struck 66 million years ago. And it was all because of a toxic plant they were munching on.

Conventional wisdom holds that the dinosaurs were wiped out by a huge asteroid slamming in the Earth and throwing up dust that blotted out the sun. But the study, published in the journal Ideas of Ecology and Evolution by scientists Michael Frederick and Gordon Gallup, suggests that there is strong evidence that the dinos were eating a plant that was killing them.

They believe the dinosaurs had not evolved the ability to recognize and avoid poisonous plants, and this was slowly killing them off before the asteroid ended them officially. Most animals today have a mechanism in their DNA that causes them to develop an avoidance to plants that make them sick through their smell and taste.

“Numerous hypotheses have been advanced to explain the worldwide extinction event that led to the disappearance of the dinosaurs,” the abstract of the paper states. “There is considerable empirical support for the well-known asteroid impact hypothesis, and volcanic eruptions in the Deccan Traps have also been implicated. Increasingly, theories involving multiple causes are being considered, yet few of these consider how the cognitive and behavioral abilities of certain classes of animals may have differed in ways that allowed some to survive while others perished. Here we advance the hypothesis along with supporting evidence that the emergence of toxic plants coupled with an inability to form learned taste aversions may have contributed to the extinction of dinosaurs.”