It’s been widely theorized throughout the years that a massive asteroid struck Earth about 66 million years ago, causing dinosaurs to go extinct mainly through that cataclysmic event. However, a new study hints that the species might have already been on the path to extinction, as toxic flowering plants had become commonplace prior to the event, with dinosaurs somehow unable to develop an aversion to their taste.
In a new study published in the journal Ideas in Ecology and Evolution, researchers wrote that some of the first flowering plants were poisonous, and showed up in dinosaur fossil records well before the asteroid impact believed to have killed off the species toward the end of the Cretaceous Period. The study suggests that dinosaurs were not able to learn how to avoid these plants in time to avoid their decline, as they lacked a taste aversion that would have otherwise warned them that certain types of food are dangerous. This is in contrast to animals such as rats that sample small amounts of food, then use their senses of taste and smell to avoid whatever foods end up making them sick.
According to study co-author Gordon Gallup, an evolutionary psychologist and professor at the University of Albany in New York, dinosaurs might have hastened their extinction by continuing to consume the toxic flowers, despite suffering from gastrointestinal issues due to their poisonous content.
“Though the asteroid certainly played a factor, the psychological deficit which rendered dinosaurs incapable of learning to refrain from eating certain plants had already placed severe strain on the species,” said Gallup, in a statement published on the University of Albany website.
As Gallup further noted, his team’s new theory on dinosaur extinction counters the existing belief that these giant lizards were wiped out across the globe through one singular asteroid impact, as it took “millions of years” for the species to disappear gradually after they were first introduced to toxic flowers as an available food source.
Aside from exploring the hypothesis that dinosaurs began to decline after exposure to toxic plants, the researchers also looked into the eating habits of birds and crocodilians to see if they are capable of acquiring taste aversions. Both species are believed to have descended from certain types of dinosaurs and were also found to be unable to avoid dangerous foods based on their taste. Birds, however, were shown to use visual cues, rather than taste, in order to avoid things that made them ill.