Nocturnal

Nocturnality is a behavior in some non-human animals characterized by being active during the night and sleeping during the day. More specifically, they have been found to have a larger cornea relative to their eye size than diurnal creatures to increase their visual sensitivity: in the low-light conditions. Cathemeral species, such as fossas and lions, are active both in the day and at night. While it is difficult to say which came first, nocturnality or diurnality, a hypothesis in evolutionary biology, the nocturnal bottleneck theory, postulates that in the Mesozoic, many ancestors of modern-day mammals evolved nocturnal characteristics in order to avoid contact with the numerous diurnal predators. The leading answer is that the high visual acuity that comes with diurnal characteristics is not needed anymore due to the evolution of compensatory sensory systems, such as a heightened sense of smell and more astute auditory systems. They indicated that olfactory bulbs were much larger in comparison to their optic lobes, indicating they both have a common ancestor who evolved to function as a nocturnal species, decreasing their eyesight in favor of a better sense of smell. A larger cornea and pupil correlated well with whether these two classes of organisms were nocturnal or not. Being active at night is a form of niche differentiation, where a species' niche is partitioned not by the amount of resources but by the amount of time . Hawks and owls can hunt the same field or meadow for the same rodents without conflict because hawks are diurnal and owls are nocturnal. Another niche that being nocturnal lessens competition within is pollination - nocturnal pollinators such as moths, beetles, thrips, and bats have a lower risk of being seen by predators, and the plants evolved temporal scent production and ambient heat to attract nocturnal pollination. Like with predators hunting the same prey, some plants such as apples can be pollinated both during the day and at night. Nocturnality is a form of crypsis, an adaptation to avoid or enhance predation. Although lions are cathemeral, and may be active at any time of day or night, they prefer to hunt at night because many of their prey species have poor night vision.