Are sharks gellin’? As it
turns out, they are. Hydrogel ensconced in large pores cover many sharks, rays
and other elasmobranchs’ snouts and heads acting as antennae for electrical
impulses in the surrounding water. The gel allows them to zero in on prey and
find potential mates, according to research by Professor of
Physics and Director of External Affairs Brandon Brown.
Brown, recently named the
winner of USF’s 2010 Distinguished Research Award handed out by USF and the USF
Faculty Association, says he stumbled into the field of shark research by
accident about a decade ago.
Although he received his
doctoral training studying the properties of exotic crystals, he became
engrossed with the ocean’s apex predator when a colleague introduced him to the
electrical sensory capabilities of hydrogel.
“From there, I turned my full
attention to studying the ability of certain animals to detect electricity in
their environments,” said Brown, who has published 10 peer-reviewed articles,
culminating in significant milestones over the last three years. “It has been
an exciting 10-year journey, and I’ve been lucky to find great students and collaborators
along the way.”
Sharks and other
elasmobranchs use the gel to detect electrical pulses in the water, somewhat
comparable to a barn owl detecting the sounds of prey in the darkness, except
over longer distances and at minute levels, according to Brown’s research, which was featured as a part of the Discovery Channel's Shark Week in August.
In swimming through these
outward spiraling electrical impulses created by the flexing fins of prey or
even by the opening and closing of gills, sharks are able to navigate toward
the source.
By comparing mathematical
models to actual shark behavior, Brown has been able to witness sharks who use
their “sixth sense” to make a beeline for the source while some, thought to be
less experienced hunters, spiral in toward the source of the electrical
impulses. Spiraling allows them to maintain the same orientation to the
impulses as they approach, so as not to lose the scent, so to speak.
“Essentially, the gel could act as a thermostat,
allowing a shark to detect minute temperature changes – like those produced by
prey – by turning those fluctuations into electric signals,” Brown said.
