Scientists are not sure when an asteroid wiped off the dinosaurs, but they know it happened in the springtime in the Northern Hemisphere. They also argue that the timing of the tragedy may have influenced which animal species survived. It had no effect on dinosaurs, but it may have had an influence on other animals, birds, and plants. This was very certainly the case for animals in the Southern Hemisphere, where the impact occurred 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 released the findings of a study of fossil paddlefish and sturgeon found in Tanis, North Dakota, showing that the fish perished in the spring.