[Animals] Descubren que las arañas saltarinas pueden experimentar sueños vívidos, como los seres humanos

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Can spiders dream? The movement of their eyes and the reactions they have when sleeping suggests that it is. This is what we know.
Jumping spiders move slowly, smoothly. They are not in a hurry. At just a few millimeters in length, they are some of the smallest arachnids in the world. However, they are also among the most agile: they can jump up to meters away, despite their small size.

In addition to being innate acrobats, it seems that jumping spiders can dream. A study recently published in the Proceedings of the National Academy of Science (PNAS) suggests the possibility that these arachnids experience vivid images when sleeping, just as mammals do. This is what we know.

We suggest: Why you shouldn't kill spiders you find at home

What happens to spiders when they enter deep sleep states?

Jumping spiders are the largest family of arachnids on the planet. According to the Naturalista platform, "constituting 13% of all species" of which there is a record. This percentage adds up to approximately 600 genera and 6000 species described.

This family of arachnids has developed movable retinas. So a team of Harvard researchers recorded in a controlled laboratory environment how jumping spiders move their eyes very quickly while sleeping. And what's more: they have reactions with the body similar to the involuntary movements that other species experience when sleeping.

Considering the above, the researchers overcome that the spiders are not only resting, but also dreaming:

"THE OBSERVED RETINAL MOTION EPISODES WERE CONSISTENT, INCLUDING REGULAR DURATIONS AND INTERVALS, AND BOTH INCREASED OVER THE COURSE OF THE NIGHT," THE SCIENTISTS WRITE. "THE FACT THAT THESE CHARACTERISTIC BEHAVIORS OF REM SLEEP EXIST IN A HIGHLY VISUAL AND DIVERGENT LINEAGE FURTHER CHALLENGES OUR UNDERSTANDING OF THIS SLEEP STATE."

The movement that scientists recorded is known as REM: Rapid Eye Movement, which translates as 'rapid eye movement'. This happens in some animals when they enter deep stages of sleep, and coincides with the dream experiences that some vertebrate animals have.

In fact, as documented by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the REM state "represents 25% of the sleep cycle and first occurs 70 to 90 minutes after falling asleep." Taking this into consideration, the researchers suggest the possibility that spiders can dream.

Beyond human cognition
For centuries, the anthropocentric view that science has had of other species has biased research on animal behavior. Under the assumption that only human beings can think and perceive the world as sentient beings, much of the current knowledge about language and cognition focused on us, nothing else.

Today, however, we have evidence that our species is not the only one that can dream. Jumping spiders seem to do it too. And not only that, they seem to have vivid dream experiences: "their legs, rows and abdomens were contracted, or their legs were curled up in what seemed to be a defensive posture", Science Alert documents about it.

Even though spiders do not have very sharp vision, they mimic the reactions they have when they are awake when defending themselves and moving around. This behavior, the Harvard researchers conclude, could shed light on the evolution and function of the REM state.

https://www.ngenespanol.com/animales/descubren-que-las-aranas-saltarinas-pueden-experimentar-suenos-vividos-como-los-seres-humanos/