If there’s one thing that most of us know about sharks, besides the fact that they occasionally bite people, it’s that they have a fantastic sense of smell - some sharks can smell a single drop of blood within a million drops of water. How do they do it? That’s what British scientists are trying to find out... and their discoveries could be applied to human technology.
Dr. Jonathan Cox, a chemist from the University of Bath, has been collaborating with researchers from the University of Cambridge and the Natural History Museum in London. They started by doing a CT scan of a preserved hammerhead shark, then making a model of it with a 3D printer. That model was then placed in a flow tank, to see how water flows through and around its nasal cavity. To simulate the head-sweeping movements that sharks make as they swim, the scientists have been changing the angle of the model head, and observing how that effects the flow.
There’s already one thing they know for sure - sharks don’t smell the same way we do.
“Whereas humans use their lungs like a bellows to inhale air through their noses to smell, the hammerhead shark smells as it swims forwards, propelling water through its nose” said Cox. “The nasal cavity of the hammerhead is like a labyrinth of pipes, with a central U-shaped channel and lots of smaller channels leading off it. The smaller channels contain the olfactory receptors, and so we’re looking at how the water flows through these channels as the shark swims forwards.”
The team hopes that their findings could be used in biomimetic technology, which is technology that emulates natural processes. One particular application could be in the design of chemical sensors, which could be used for underwater exploration, medicine or counter-terrorism.
All photos courtesy Nic Delves-Broughton.
