No animal is scientifically proven to never sleep from birth to death, but some, like bullfrogs, have long periods of dormancy instead of true sleep, while sharks rest by drifting or "stationary rest," and flying birds like alpine swifts can sleep in micro-bursts while airborne, as all complex animals need some form of rest for survival, even if it's not typical sleep.
WHAT ANIMAL NEVER SLEEPS? HERE ARE 12 THAT COME CLOSE
Bullfrogs. These giant reptiles are one of the few animals that don't ever sleep. The simple explanation is that they don't need to because they don't have a sleep-wake cycle. Bullfrogs will instead enter a dormant state, which means that their activity and metabolisms drop significantly.
Bullfrogs are among the few animals that do not sleep. Researchers have shown that they are active even while resting. They have alert periods and resting periods instead of sleep. Dolphins have a very unique form of rest called unihemispheric sleep.
Insects are no exception. Sleep signatures in insects resemble those in other animals. While insects can't physically get some “shuteye” (hard to do without eyelids), they do enter a state of metabolic rest that science has defined as “sleeping” based on other behavioral cues.
🐌 Did You Know this amazing animal fact? A snail can sleep for up to 3 years! Yes, some snails can hibernate or go into deep sleep to survive harsh weather.
Nonetheless, soaring frigatebirds appeared to use unihemispheric sleep to watch where they were going while circling in rising air currents. Despite being able to engage in all types of sleep in flight, the birds only slept for 0.7 h d−1 during flights lasting up to 10 days.
Fish Sleep FAQs
Yes. Fish sleep with their eyes open because they do not have eyelids.
Koalas are thickset arboreal marsupials with a thick grey fur. Found only living in Australia, they mainly live in the eucalyptus trees and spend around 22 hours of their time sleeping (90%).
However, unlike other mammals, adult dolphins and whales are able to go without sleep for a month.
The answer is “probably.” Research has shown that many animals experience a sleep phase similar to humans known as REM (Rapid Eye Movement) sleep, which is closely associated with dreaming. This phase is characterized by increased brain activity and is when most vivid dreams occur.
Fish are also unable to enter REM (rapid eye movement) sleep and therefore cannot dream – their brains are not developed enough for this. However, although opinion still varies, there is some evidence to suggest that fish (just like other animals) use sleep as a means of memory-processing and learning.
Are Fish Capable of Feeling Pain? The simple answer is yes. Many scientific studies over many years have demonstrated that fish feel pain. To be precise, this doesn't just mean that fish physically react to potentially injurious stimuli, but rather, that they actually experience a sensation of pain.
While most fish remain motionless when they're sleeping, certain species of sharks must keep moving, even while at rest, to ventilate their gills.
Ostriches, which are the biggest birds in the world, are the only birds known to release the two substances separately opens in a new window. Excreting waste as a thick substance means that birds don't have to fly around carrying a heavy tank of urine. In fact, birds don't actually have bladders to store pee in.
Besides owls, bat hawks, frogmouths and nightjars also display good night vision. Some bird species nest deep in cave systems which are too dark for vision, and find their way to the nest with a simple form of echolocation.
It's thought they do this by switching off one half of their brain during unihemispheric slow wave sleep (USWS), so one half can rest while the other stays active. Swifts also have some other inventive techniques for survival. They drink by gliding over water and taking sips, or by catching raindrops.
Most scientists agree that the most likely reason why 17-year cicadas spend so long underground is to avoid predators. By coming to the surface in such a large group, some cicadas get eaten but many cicadas will survive.
Additionally, jerboas have large ears to help them detect the slightest sound, which could be an approaching predator. They get their water from the plants and insects they eat, going their entire three-year lifetime without drinking liquid water.
On average, a snail can sleep for 13 – 15 hours a day. This doesn't leave much time for exploring. They can even hibernate for 3 years! (Remember, hibernating is not the same as sleeping and hibernating for this long can mean their environment is too cold or dry).
Yes, spiders do sleep (or at least enter a sleep-like state that's very similar to our form of slumber). Much like us, spiders need a deep rest state to keep their brains functioning and their bodies healthy.
Bugs hate strong, pungent, or overpowering natural scents, with peppermint, citronella, lavender, eucalyptus, and tea tree oil being top contenders, alongside vinegar and certain herbs like basil and rosemary, which disrupt their navigation and sensory systems. While no single scent universally repels all bugs, these strong aromas create an unpleasant environment, making them effective natural deterrents for common pests like mosquitoes, ants, and flies.
How do we know that insects sleep? Butterflies and other insects cannot close their eyes when they sleep, because they do not have eyelids. However, they do enter a typical “sleep posture”. For example, some native bees spend the night on a plant stem, holding on with just their mouthparts.
They can and will see you if you do not take care in your approach and your presentations to them. Once you're spotted and one fish spooks, they will send alarm bells to all the rest of the fish in the spot and your chances of catching a spooked fish are zero.