

Despite this growing popularity of pupillometry, the methodological understanding of pupillometry is limited, especially regarding potential factors that may threaten pupillary measurements’ validity. Pupillometry, thanks to its strong relationship with cognitive factors and recent advancements in measuring techniques, has become popular among cognitive or neural scientists as a tool for studying the physiological processes involved in mental or neural processes. You can follow writer Wynne Parry on Twitter. The research appears in the most recent issue of the journal Science. These results indicate that dinosaurs and early mammals did not split the day and night in fact, it's not yet clear whether early mammals were nocturnal at all, and that idea needs to be evaluated, Schmitz said. This attack probably happened in the twilight or low-light conditions, the researchers write. For instance, fossil evidence has documented an attack by one of these night dwellers, Velociraptor mongoliensis, on the periodically awake Protoceratops.

The finding could help to set the stage for other dinosaur findings. Predators, both dinosaur and modern, gain an advantage by hunting at night, and all of the dinosaur predators analyzed were either nocturnal or periodically active. Large animals are also more prone to overheat, so they try to avoid being active during the heat of the day, shifting their activity into nighttime hours, according to Schmitz. For herbivorous animals, like elephants and the herbivorous dinosaur Protoceratops andrewsi, larger size means a need to spend more time foraging and eating. Most of the plant-eating dinosaurs were awake periodically. They then compared this information with data from living species. They looked at the size of the opening inside the scleral ring, where the pupil would be, as well as the eye socket to determine the diameter of the eye, and at the diameter of the external edge of the scleral ring to determine the length of the eye. In the fossils, researchers examined the proportions of certain features of the eye to determine a species' habits. As a result, they have an intermediate-size scleral ring - among those that have this bone - and an overall larger eye. Their eyes need both acuity and a good sensitivity to light. Other animals are active at dusk and dawn or at sporadic intervals throughout the day - nowadays this includes large herbivores, like the fallow deer, certain birds, the large hairy armadillo, the Amazon tree boa and even dogs. A smaller opening reduces the amount of energy these animals have to spend constricting their pupils to reduce the amount of light coming in, and it also allows them to see a clear and focused image at a large range of depth, according to Schmitz. Daytime living species, meanwhile, have much more light with which to see. Nocturnal animals need to let the maximum amount of light possible into their eyes, so they need a larger opening within the scleral ring.
