Orb-weaver Spider Baffles Scientists with Pulsating Disco Moves

Scientists and spider experts are baffled with the pulsating membrane of the orb-weaver spider, which resembles blobs of ink dancing to a certain tempo.

Scientifically known as Cyrtarachne inaequalis, National Geographic released a video of the arthropod filmed by photographer Nicky Bay. The video shows what seems to be a smiling snake head with blotches pulsating below its eyes. However, further into the video, the camera shifts and reveals an orb-weaver spider.

Scientists reveal that the swirling blob is part of the spider's abdomen which may be a defense mechanism or a mating scheme for their species.

Linda Rayor, a spider biologist at Cornell University sees it as "bizarre and interesting." Being a world specialist on spider behavior, Rayor admits that she hasn't "seen anything like it."

The author of the book Biology of Spiders Rainer Foelix says that "people love to jump to conclusions what such a behavior is good for." But scientists are yet to tell what the puzzling behavior is for.

In 2015, this spider also caught the attention of people in India at an Entomology Facebook page describing the amazing display of the spider.

Experts say that spiders do some pretty crazy things, like disguising themselves as leaves or ladybugs, tap-dancing for love, and sculpting fake spiders to hang as decoys in their webs. However, little is known about the abilities of spiders to change their appearance.

"Rather than to speculate, it would be better to study this phenomenon scientifically," Foelix added.

The Cyrtarachne species are also known as bird-dropping spiders due to its color resemblance to bird droppings.

Professor at the Department of Biological Sciences in the University of Pittsburgh Nathan Morehouse agrees that further studies need to be concluded to fully understand the arthropod.  

"Without a better handle on how variable this is within the population, it's difficult to make any headway with hypotheses about [what it could be mimicking]," Morehouse says.

Morehouse added that he'd "start with trying to understand what the membrane is that's moving, and why it might be moveable. And why it might be colored."