When you picture a sleeping animal, you probably think of a dog twitching by the fire or a cat curled on a windowsill. You almost certainly do not picture a spider. Yet a new study has filmed tiny jumping spiders doing something that looks remarkably like the REM sleep we have long thought of as ours alone.
It is a small, strange finding with a surprisingly big implication. The kind of sleep in which we do most of our dreaming may be far older, and far more widespread, than anyone assumed.
The short answer. Researchers recorded Australian jumping spiders cycling through a quiet rest phase and then a REM-like phase, complete with twitching legs and moving eyes. It suggests REM sleep is ancient and shared across very distant branches of the animal family tree, though scientists are careful not to claim spiders dream the way we do.
What the study actually found
The research, published in the journal Proceedings of the National Academy of Sciences and led by behavioural ecologist Daniela Rossler at the University of Bonn with colleague Nadja Geiger, focused on the fringed jumping spider, Portia fimbriata, a species found across northern Australia. As reported by ABC News, the team filmed the spiders overnight as they hung upside down in small resting webs, a position that made their sleep easy to study.
What they saw came in at least two phases. First a quiescent phase, with slow drooping movements and grooming. Then a REM-like phase, marked by curling legs, twitching limbs and movement of the retinas behind the spiders' large forward-facing eyes. When the researchers played a loud noise, the spiders were slower to react during these rest phases, and some in the REM-like phase did not respond at all, a sign they were genuinely asleep rather than simply still.
It is worth being honest about the limits. This was lab work, not fieldwork, and the team itself plans to study spiders in the wild next to see how natural conditions change their rest. Comparing a spider's twitching legs with a human's rapid eye movements also involves a degree of inference. One outside researcher noted that lining up spider behaviour with vertebrate sleep is interpretation, not proof. And the idea that sleep's basic architecture is ancient is presented by the scientists as a strong possibility, not a settled fact. What the footage shows clearly is a repeating, sleep-like cycle. What it means for the deep history of sleep is the exciting part still being worked out.
What it means for your sleep
You are not a jumping spider, so why should this matter to you on a quiet Tuesday night? Because it is a reminder of how fundamental REM sleep seems to be. If a creature whose last common ancestor with us lived hundreds of millions of years ago still cycles through a REM-like state, then REM is not a quirky human luxury. It is almost certainly doing something essential.
In humans, REM is the stage most tied to vivid dreaming, to processing emotion and to consolidating what we have learned during the day. It tends to cluster in the second half of the night, which is exactly the part of your sleep that gets trimmed when you go to bed too late or wake too early. If you have ever wondered why a short night leaves you flat and foggy even after coffee, a shortage of REM is often part of the story. We go into more detail in our guide to what REM sleep is and why your brain comes alive during it, and in our look at why we dream.
The practical takeaway is simple: protect the back half of your night. That means a consistent wind-down, a dark and cool room, and as little disturbance as possible once you are under. The spider study is a neat illustration of that last point. The researchers used noise precisely because a sudden sound is one of the easiest ways to interrupt rest, and that is just as true in a bedroom as in a lab. If traffic, a snoring partner or thin walls keep pulling you back to the surface, a soft set of earplugs can take the edge off the noise so your sleep can run its full course. They will not fix a noise problem at its source, but for many people they are the difference between surfacing all night and sleeping through. If your nights are genuinely loud, our guide to sleeping with noisy neighbours covers the sturdier fixes too.
Quick questions
Do spiders actually dream? We honestly do not know. The study shows a REM-like phase with the physical signs we associate with dreaming in other animals, but no one can ask a spider what, if anything, it experiences. The scientists are deliberately cautious on this point.
Why does REM sleep matter for people? REM is strongly linked to emotional processing, memory and mood. Too little of it tends to leave you feeling mentally dull and more easily rattled the next day.
How do I get more REM? You cannot force a single stage directly, but you can give it room. Going to bed early enough to get a full night, keeping a steady schedule and easing off late alcohol all help, since REM is concentrated in the final hours of sleep.
This article is general information, not medical advice. If your symptoms are persistent or severe, or you are unsure what is causing them, please speak to your GP. SleepyDeepy products are designed to support your sleep and are not a treatment for any medical condition.
Sleep well, and spare a thought for the little spiders twitching through their dreams in the Australian scrub. Nature worked out the value of a good night long before we did. SleepyDeepy.
