Fishes' Lateral Lines Sense Pressure and Predators
A lot of fishermen will tell you that fish have kind of a sixth sense. They avoid obstacles, effortlessly slalom between vortices or whirlpools, and hide from predators—even when they can’t see. But how do they do it?
Researchers from the University of Florida and New York University think they’ve found the answer. Nearly all fish, they say, have a similar network of sensors along their bodies that are exquisitely sensitive to changes in water pressure. The report is in the journal Physical Review Letters. [Leif Ristroph, James C. Liao and Jun Zhang, Lateral Line Layout Correlates with the Differential Hydrodynamic Pressure on Swimming Fish]
For the study, the researchers made a plastic rainbow trout with an accurate configuration of flow sensors on its body. Known as the “lateral line,” these sensors apparently act like a hydrodynamic antenna, picking up signals about the flow of water around them.
They put the fake fish in water, and simulated important real-life situations—for example, a bigger fish swimming nearby that might want to turn the trout into sushi. The researchers noted that the natural setup of the fish’s sensors includes a higher density of them on the parts of the body subject to the greatest pressure changes. So the sensory awareness of its environment is highly resolved—showing that the notion that fish have a sixth sense isn’t fishy at all.
—Gretchen Cuda Kroen