Alligators use special sensors to detect motion in nearby waters
They may look as tough as rawhide, but alligators have a sensitive side. Thousands of small nodules--sprinkled across the creatures' faces like stubbly beards--are highly responsive pressure detectors, according to a recent study.
Alligators hunt mostly at night, floating partly submerged and seizing unsuspecting prey. To see if the pentip-sized nodules played a role in hunting, neuroscientist Daphne Soares put young alligators in water tanks in complete darkness and plugged their ears. She then splashed droplets onto the water and recorded the creatures' reactions with infrared film. The temporarily blind and deaf gators turned toward and lunged at ripples from a single drop of water, says Soares, now at the California Institute of Technology. When the nodules were covered, the alligators failed to react to the drops.
One practical lesson from her work is simple, Soares says: "Don't go splashing around if you're in a pond full of alligators."