Search results
Results from the WOW.Com Content Network
Crepuscular, a classification of animals that are active primarily during twilight, making them similar to nocturnal animals. Diurnality, plant or animal behavior characterized by activity during the day and sleeping at night. Cathemeral, a classification of organisms with sporadic and random intervals of activity during the day or night.
A group of muskoxen in Alaska. The biodiversity of tundra is low: 1,700 species of vascular plants and only 48 species of land mammals can be found, although millions of birds migrate there each year for the marshes. [9] There are also a few fish species. There are few species with large populations.
Both plant species and animal species have become endangered. The Aleutian shield fern is a plant species that have been endangered due to caribou tramping and grazing, slumping from growing substrate, and human foot traffic. [9] Animal species that are endangered in the tundra include the Arctic fox, caribou, and polar bears.
Nocturnal luminosity has been found to positively correlate with the amount of nocturnal activity and negatively correlate with diurnal activity. In other words, an animal's activity distribution may be somewhat dependent on the presence of the lunar disc and the fraction of illuminated moon in relation to sunset and sunrise times.
The kiwi is a family of nocturnal birds endemic to New Zealand.. 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. [3]
Initially, most animals were diurnal, but adaptations that allowed some animals to become nocturnal is what helped contribute to the success of many, especially mammals. [7] This evolutionary movement to nocturnality allowed them to better avoid predators and gain resources with less competition from other animals. [ 8 ]
Mustelids are some of the most important predators of squirrels, mice, and voles, although wolverines can take down an animal as large as a caribou and the primary food of river otters is fish. Several species, including the river otter, black-footed ferret, and wolverine, have declined over much of their range because of habitat loss ...
Some species that always live in shoals or that swim continuously (because of a need for ram ventilation of the gills, for example) are suspected never to sleep. [4] There is also doubt about certain blind species that live in caves. [5] However, other fish do seem to sleep, especially when purely behavioral criteria are used to define sleep.