A team of scientists of New York University and University of Florida has identified how a “sixth sense” in fish allows them to detect flows of water, which helps resolve a long-standing mystery about how these aquatic creatures respond to their environment. Their findings, which appear in the journal Physical Review Letters, illustrate how sensory systems evolve in accordance with physical principles while also offering a framework for understanding how sensory networks are structured.
“We identified a unique layout of flow sensors on the surface of fish that is nearly universal across species, and our research asks why this is so,” explains Leif Ristroph, an assistant professor at New York University’s Courant Institute of Mathematical Sciences and one of the study’s authors. “The network of these sensors is like a ‘hydrodynamic antenna’ that allows them to retrieve signals about the flow of water and use this information in different behaviors.”
It is well known that fish respond to changes in their fluid environment. These include avoiding obstacles, reducing swimming effort by slaloming between vortices, or whirlpools, and tracking changes in water flow left by prey—even without the aid of vision.
To explore how fish exploit flow information, the research team focused on a fish’s “lateral line”—a system of sensory organs known to detect both movement and vibration in the water that surrounds them—with particular consideration to the line’s sensory-laden canals that open to the environment through a series of pores. They specifically focused on the placement of these canals along the body, noting that their location can help explain how a fish’s sixth sense functions. For instance, the concentration of these canals at the heads of blind cave fish seems well-suited for detecting obstacles.
For details, please visit the website of New York University.
