DESPITE their tiny brains, fiddler crabs excel at trigonometry. Fiddlers constantly watch for other crabs that might steal their burrow, and when one nears, they can accurately triangulate the distance between that crab and their burrow, even if they have wandered so far they have lost sight of home.
Fiddlers’ eyes are adapted to their mudflat habitat, so an intruder’s position relative to the guarding fiddler is determined by its distance below the horizon. The intruder’s proximity to the burrow is then estimated by combining this with the fiddler’s inbuilt “walking odometer”, which tells it how far it has wandered from home. “These are very accurate…
