New Study Finds Sharks Can Switch Among Different Senses When Hunting Prey

A new study finds that sharks have the ability to switch between multiple senses to hunt down their prey.

The Bradenton Herald reports that the study shows how touch, vision, smell and other senses come together to guide shark behaviors.

The results of the Florida study showed that different shark species favor different senses when hunting, and that the senses sometimes switch when preferred senses are blocked.

"They can go to an alternate sense," said Jayne Gardiner, a postdoctoral fellow at Sarasota's Mote Marine Laboratory.

Three shark species—bonnethead, nurse and blacktip—were studied in a large tank at Mote Marine Laboratory. Researchers dangled a fish or shrimp at the opposite end of the tank, then released a hungry shark and tracked its movement toward the prey.

They then blocked the shark's senses one by one, using eye coverings, nose plugs and antibiotics to interfere with lateral lines that detect water motion. They also used electrical-insulating materials to block the electrosensory pores on their snouts.

Gardiner said the most surprising finding in the study was "the flexibility of the behavior use of sensory cues, the fact they were able to switch when the preferred senses became unavailable. They could switch to an alternate sense."

She also said it was surprising to find that they use other senses besides smell to catch prey.

"We often talk about sharks as swimming noses ... all sorts of things about their incredible sense of smell, but not all sharks need smell to feed," Gardiner said. "A nurse shark relies on smell. It can locate a fish, but it won't eat the fish unless they can smell it. But the blacktip and the bonnethead did just fine without smell. They did it visually."

The findings show that sharks can feed in a wider variety of environments than was previously believed.

The study is the most comprehensive multi-sensory work on any shark, said co-author Philip Motta, a professor at the Tampa campus of USF.

"Perhaps the most revealing thing to me was the startling difference in how these different shark species utilize and switch between the various senses as they hunt and capture their prey," he said. "Most references to shark hunting overemphasize and oversimplify the use of one or two senses. This study reveals the complexity and differences that are related to the sharks' ecology and habitats."