Tarantulas calculate Distance with their 3 billion eyes

Spinnen berechnen ihre Wege mit ihren gegenüberliegenden Augenpaaren und konstruieren spinnensinnmäßig ein rechtwinkliges Dreieck, auf dessen Hypotenuse sie sich dann entlangbewegen. Geometrisch denkende Mathe-Taranteln also, na prima. --> phys.org: Tarantula wolf spiders use their lateral eyes to calculate distance

Tarantula wolf spiders have four sets of eyes, and a study from the Autonomous University of Madrid shows that they use their posterior lateral eyes and anterior lateral eyes to establish the distance they have traveled.

The tarantula wolf spider species Lycosa tarantula ambushes its prey and lives in burrows around 20 cm deep topped by a structure, a kind of turret that the tarantula build from twigs, leaves and small stones, fastened with spider's silk. From the turret, the tarantula surprises its prey and runs to pursue it, subsequently returning to the burrow from distances between 30 and 40 cm.

L. tarantula uses path integration to return to its burrow. With this mechanism, it does not follow the same path back to its burrow; instead, it moves as though it had followed the sides of a right-angle triangle, returning along the hypotenuse. […] The tarantula wolf spider's median eyes measure the angle of polarised light, comprising its 'compass'; it detects direction using its anterior lateral eyes. Through this research, the scientists have learned that it is principally the anterior lateral eyes—which until now had not been analysed—and to a lesser extent, the posterior lateral eyes, that tarantula wolf spiders use to measure the distance to their nest.