Scientists discovered an extraordinary feature in tarantula spider’s body, they have built in compass and odometer in their body. They have found the four sets of lateral side eyes help them to measure the distance from their nest or the position of their prey.
Researchers from the Autonomous University of Madrid studied on the tarantula spider species called Lycosa tarantula from the native habitat of Southern Europe. They prefer to live inside the trees by digging a hole about 20 centimeters deep where they use twigs, leaves and their silk to build nests. Mail Online reported that tarantulas spiders spy on their prey from the tree and surprise the prey when it’s in the range of 11.8 to 15.7 inches.
Tarantula spiders use path integration method to return to their nest. Most interesting fact is that they don’t follow the same path while returning home. They always cover a right-angle triangular path and at the time of return, they use the hypotenuse of the triangle.
As per the report by Phys, in 1999 scientists from the same university has discovered that tarantula spiders use polarized light from the sky to navigate. In this current research, the team is analyzing how tarantula spiders use their four pairs of lateral eyes in the function of odometry.
Lead researcher Dr. Joaquin Ortega Escobar said in his report,“To calculate the distance it has traveled, the animal needs an odometer that registers the route, its location with respect to the finish point, which would be the burrow, and a 'compass' to track the direction of travel”. He also explained that tarantula spiders use their median eyes to calculate the angle of polarized light which helps them to navigate. when the direction is detected then they use their lateral eyes to measure the distance.
During the experiment, Escobar and his team covered their lateral anterior eyes and found all of the tarantula spiders were unable to move. In contrast, when they removed the cover then they have started moving like before. From this study scientists came to the conclusion that anterior lateral eye perceives the ventral field of view, so without those eyes, they just lost the perception of distance, angle, and depth.
