Scientists are not sure exactly when an asteroid wiped off the dinosaurs, but they know it happened in the Northern Hemisphere in springtime. They also suggest that the disaster’s timing may have played a factor in determining which animal species survived. It had little effect on dinosaurs, but it may have had an impact on certain creatures, birds, and plants.

This was most likely the case for animals in the Southern Hemisphere, where the impact would have happened in the autumn or early winter. “In the Southern Hemisphere, many organisms would have been in hibernation or sheltering. That could have helped them,” explains Melanie of Uppsala University in Sweden. “In spring, you expect animals to be tending to their offspring which are very fragile, or perhaps they are still tending to eggs, waiting for them to hatch or be looking for food. That puts them in a vulnerable position.” Ms. During recently published the results of a study of fossil paddlefish and sturgeon discovered near Tanis, North Dakota, which show that the fish died in the spring. Tanis is the location that records not only the day a 12-kilometer-wide asteroid slammed into the Earth 66 million years ago but also the minutes and hours that followed.