Are We Sure We Want to Know What Spiders Are Dreaming About?

Scientific research and discovery is a strange and wonderful area. It helps us better understand the universe and our place in it. Lately, however, some more creepy finds have come from our scientist friends. First, there was the news about creating micro-robots out of spider cadavers (that gave me a few sleepless nights). Then there was the sound recording of space that sounds like 1,000 souls being sucked into the void.

Recently, a behavioral ecologist from the University of Konstanz in Germany published her findings on a sleep study performed on spiders. Daniela Roessler spoke with NPR about her research on jumping spiders and REM sleep. In humans, REM (Rapid Eye Movement) sleep is associated with dreaming. So, do spiders really dream?

Dream a Little Dream of Me

I want to preface the rest of this article with the confession that I am terrified of spiders. I cannot stand them. Even reading too much about them or looking at pictures of them causes me to get overwhelming feelings of icky. So I am a little biased about the nasty little things. However, I had to read about the study to know if the arthropods are planning world domination or something. Know your enemy, right?

Roessler focused her studies on the jumping spider. Unlike other spiders, they have very good vision. They have also been seen to change their hunting techniques based on the prey they are going after, showing a level of intelligence. Roessler also claimed jumping spiders are the “cute” ones.

With humans, when we go into REM sleep we move our eyes around and sometimes other parts of our bodies while we dream. Scientists have found some animals also experience this phenomenon. Roessler tested jumping spiders for evidence of REM sleep. In the study, she set up night vision cameras to watch the spiders during dark hours to monitor their sleep cycles.

At night, adult spiders would curl up and remain in the same spot but would twitch from time to time as humans do during dreaming. Spiders can’t move their eyes as humans can. To judge the eye movement of the spiders, Roessler watched baby spiders. The young ones are translucent so it is easier to track changes in their ocular tubes (gross, I know) and found movement there as well.

Times Have Changed

While reading Roessler’s study, I realized how much things have shifted in scientific animal research fields. Historically, non-human animals were viewed as less advanced than humans. Some claimed animals couldn’t feel pain or have emotions, justifying horrific experiments (which sadly still occur). Over the past thirty years, a general shift in cultural attitudes towards animal rights has changed research. Instead of just using animals to further our knowledge of humans, scientists have been more closely studying the animals themselves.

For many years there has been anecdotal evidence about animals “being just like us” (the book When Elephants Weep is a great example of animal emotion stories). But it wasn’t until more recently that scientific studies of emotions, intelligence, and cognition have been more thoroughly explored in the animal kingdom. Just this year, the United Kingdom government passed a bill qualifying animals (including octopus and lobsters) as sentient creatures based on hundreds of studies. Meaning they can feel pain and other emotions.

Now, we are exploring sleep cycle patterns in animals. Beyond Roessler, other researchers have recorded REM-like sleep activity in birds, most mammals, some insects, and cephalopods. The purpose is to figure out why we all have this common thread while we sleep. Why did this activity evolve across species? But just because something experiences REM sleep, it doesn’t necessarily mean dreams are occurring. More research will have to be done to come to conclusions on that front.

Roessler pointed out that dreams may look different in other species. Since most spiders rely on vibrations rather than sight, their dreams might be just vibrations. I know that sentiment should put me at ease, at least they probably aren’t dreaming of eating us. Probably. Though, vibrations dreaming sounds even more nightmarish.

(image: Marvel/Sony)