Worms have a specific antenna-shaped neuron that senses the Earth's magnetic field, enabling the transparent nematode to know up from down when it's in the ground.
"This is the first discovery of an actual sensory neuron that detects the Earth's magnetic field," says neuroscientist Jon Pierce-Shimomura. "Birds, turtles, butterflies and many other animals can sense the magnetic field for their impressive migrations. But researchers are still searching for the neurons in these animals that sense the magnetic field."
