Do you have nightmares about spiders? What about flies, humans, or anything else?
Thousands of species of jumping spiders might experience rapid eye movement stages of sleep according to a US- European research partnership. The state in which humans have their most vivid dreams is that, though the study doesn't conclude that spiders have dreams.
The arachnids were observed by the team from universities in Germany, Italy and Harvard University in the US, and they found that the arachnids were active during the night.
While the researchers are not spinning a tale that spiders were definitely experiencing anything close to human-like patterns of sleep, they said it left them "begging the deeper question of whether jumping spiders may be experiencing visual dreams".
The lead author of the study told Scientific American that the twitching was similar to when a dog or cat dreams.
She said in a separate interview with the Washington Post that it was not the same as seeing a visual dream.
She said the spiders could be having dreams.
The findings were published in a peer reviewed journal.
Research into insects and arachnids is rare in the study of REM sleep.
The study notes that mosquitoes have evolved only in a limited number of lineages.
Spiders that jump have tubes that help them to look in a different direction.
Lisa Taylor is a research scientist at the University of Florida and an expert in jumping spiders.
According to Taylor, they have good cognitive abilities. They are very active in the day, they are constantly moving, they have small hairs on their bodies, and they can hear and see.
There is a lot of cool stuff going on in their brain at night. It wouldn't be surprising if they were doing that at night because they have to process all this information.
Taylor wondered if spiders had dreams. That may be better left to the artists.
The researchers stress that before they can address whether spiders have dreams, they first need to prove they are sleeping, which they intend to do in the future. The evidence they have seen suggests it was possible.
They said that twitches and Leg Curls appeared to be different expressions of the same active sleep phase.