Spiders with their eyes seem to be able to distinguish between things that are real and things that are not.
In a test in 2021, the wild jumping spiders behaved differently when presented with different types of objects.
The research shows that this ability can be found more widely in the animal kingdom than we know, and that it could be used to test other invertebrates in the same way.
The researchers wrote that the results clearly show the ability of jumping spiders to discriminate.
The presence of a biological motion based detection system in jumping spiders deepens questions regarding the evolutionary origins of this visual processing strategy and opens the possibility that such mechanisms might be widespread across the animal kingdom.
Creatures should be able to distinguish between living and non living things. It might be a matter of life or death.
It was not clear whether small animals rely on the ability to distinguish between motion and non- motion.
Spiders with good vision seem to be an excellent candidate for testing. Like most spiders, they have eight eyes, but the eyes of jumping spiders have two large pools of limpid black on the fronts of their little faces.
The team of researchers led by De Agr collected 60 samples of M. semilimbatus. The spiders were subjected to a point light test.
This is how it worked. Humans can recognize the pattern of motion as belonging to a human when presented with 11 moving dots. The 11 dots will not convey the same meaning.
The point-light display was designed by De Agr and his team. They designed other point-light displays, including a moving ellipse, and a random motion that didn't look like the movements of a living creature.
The spider's body was fixed in place over a spherical "treadmill" that rolled over a stream of compressed air.
The spider's attempt to walk over the treadmill was seen as an indicator of its response to the animations.
The spiders were shown point-light displays and their reactions were recorded.
The jumping spiders looked at the displays that were not as realistic as they would have liked. The effect was most noticeable with the randomized point-light display.
The team realized how the spider's eyes work. The secondary eyes on the side of the head give the spider a lot of vision.
If the spider spots something that it can't see, but also something that it can't see, it will prioritize the strange thing since it will remain in its field of view.
The other random motion is weird and the secondary eyes don't understand it, according to De Agr.
In order to learn more about how this ability evolved, the team wanted to use their system to apply their test to other animals.
The spiders were returned to the wild unharmed.
The research has appeared in a journal.
The first version of this article was published in July of 2011.