Nocturnal animals are primarily active at night rather than during daylight hours. There are all sorts of reasons why this behaviour might be a good idea. In hotter places such as the tropics, it's cooler at night. If you're a bat, then your ancestors took to the night skies to avoid competition for resources from birds. And, of course, it's easier to hide from predators under cover of darkness.
Kinkajous are perfectly designed for life in the trees at night.
Kinkajous are perfectly adapted for life in the trees at night, only coming out in the dark when there is little competition for food. Large eyes help them see at night but their most important sense is smell, which they use to navigate at night. Kinkajous mark their trails through the trees using scent glands on their face and stomach to leave a smelly map of their routes. They are also very flexible and a prehensile tail allows them to bend and stretch to find the very best food during their nocturnal foraging trips.
Bull sharks can survive in freshwater and incredible senses allow them to hunt at night.
Bull sharks are more commonly seen in the planet's seas but they also live in freshwater. They can hunt 24 hours a day by using acute senses that allow them to hunt in murky rivers at night. Finding electrical charges given off when prey use their muscles and a superb sense of smell that can detect one part blood per million parts water are key to their success. Sharks also have a lateral line sensitive to motion and can feel a fish swimming near them, a bit like feeling the wave of pressure left as a large truck rushes past you on the road, as Bryson Voirin explains.
Net-casting spiders build very special webs in order to snare their prey.
Net-casting spiders build special webs as Dr George McGavin explains. They first construct a framework from which to hang, before producing a different type of silk to make their net. This net is constructed when the front legs are stretched, meaning it is loose as they wait in ambush. When prey trigger their attack, the spiders stretch their legs out and downwards to throw the net over the animal, ensnaring them in a split-second.
Opossums are perfectly adapted to a nocturnal lifestyle.
Opossums are the only native marsupials found in North America. Although more commonly known as possums, they should not be confused with the other order of possums found in Australasia. Opossums spend the day safely hidden in hollow trees or holes in the ground but they have a suite of super senses that makes them perfectly adapted to life at night. They find food by smell rather than sight, aided by long, tactile whiskers to feel their way in the dark. They are omnivores and will eat almost anything they can find. Their hearing protects them from predators, particularly when they leave the relative safety of the trees to forage on the ground.
The secrets of a net-casting spider’s ambush are revealed with slow-motion filming.
This astonishing slow-motion footage of a net-casting spider's ambush reveals how they use a combination of senses to catch their prey unawares. Good eyesight allows them to see potential prey during the night, but their attack is also triggered by vibrations sent to them via a network of trip wires. One brief shockwave sent along the silk to the spider from this cricket's antenna produces an incredible hunting technique from the spider.
Nocturnality is an animal behavior characterized by activity during the night and sleeping during the day. The common adjective is "nocturnal".
Nocturnal creatures generally have highly developed senses of hearing and smell, and specially adapted eyesight. Some animals, such as cats and ferrets, have eyes that can adapt to both low-level and bright day levels of illumination (see metaturnal). Others, such as bushbabies and (some) bats, can function only at night. Many nocturnal creatures including tarsiers and some owls have large eyes in comparison to their body size in order to compensate for the lower light levels during the night.
Diurnal animals, such as squirrels and songbirds, are active during the daytime. Crepuscular species, such as rabbits, skunks, cats, and hyenas, are often erroneously referred to as nocturnal. Cathemeral species, such as fossas and lions, are active both day and night.
Take a trip through the natural world with our themed collections of video clips from the natural history archive.
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