Last updated February 13, 2018 at 9:10 am
It’s the result we’ve all been waiting for – the gold medal for Fastest Leg-driven Turning Maneuver Of Any Terrestrial Animal (aka fastest spin) goes to the spider family Selenopidae.
Researchers have just described how these creepy crawlies (commonly known as flattie spiders or wall spiders, and found in the Americas, Africa, Asia and Australia) can turn to strike their prey at speeds of up to 3000 degrees per second. In the literal blink of an eye, these spiders can rotate three times. This ability puts them in the same league as hummingbirds and fruit flies.
To map the mechanics of this incredible movement, researchers set up high-speed cameras and released crickets as prey for their spider subjects to pounce on.
Spidey senses
Even though the spiders have eight eyes, they detect their prey via disturbances in the surrounding air current. No matter which direction they sense the prey coming from, they can use their speedy spin thanks to their stance: parallel to the ground with each leg facing a separate direction.
According to lead author Dr Yu Zeng, “We found that the leg nearest the prey anchors to the ground, creating a leverage point from which the spider can pull in its torso closer to the prey.”
Meanwhile, the legs furthest away push off the ground to create the torque necessary to propel such a fast spin. As they turn, the spiders pull their remaining legs off the ground and close to their bodies, making their spin 40 per cent faster. This is a bit like figure skaters pulling in their arms to spin faster.
“About half of all spiders species don’t use webs to catch prey. Some stalk and pounce, while others are sit-and-wait ambushers–like flattie spiders,” says researcher Dr. Sarah Crews. “Flattie spiders are always one step ahead in this evolutionary arms race between predator and prey. If the prey are positioned further away, spiders move faster both linearly and with increasing rotational speeds–there’s truly no escape.”
Inspiring robotic movement
Not only is this observation interesting, it is potentially very useful for robotics, explains Dr Zeng.
“We are documenting and modeling their fast spins to help chart a course for making robots and other machines more maneuverable. Drawing inspiration from biodiversity like flattie spiders can lead to fascinating technological insights.”
© 2015 Dr. Yu Zeng
This research was published in the Journal of Experimental Biology.
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