TAMPA, Fla. (970 WFLA) – A new study sheds light on how sharks sense their prey.
The study was led by scientists from the Mote Marine Laboratory, the University of South Florida, and Boston University. They say it is the first to show how vision, touch, smell, and other senses work together in animal behavior. Results show that sharks with different lifestyles may favor different senses, and they can sometimes switch when their preferred senses are blocked. The ability to switch between senses is what scientists say impressed them the most.
Scientists say understanding how sharks sense and interact with their environment is important for shark survival, and those predators support the health of the oceans around the world.
Past studies suggested sharks sense the smell of prey, feel the water movement, and then see it as it gets closer, according to scientists, but they say no study has show how those senses work together – until now.
Researchers put three species of sharks found along the Florida coast – blacktip, bonnethead, and nurse – into a large tank where the water flowed straight toward them. They dangled a prey fish or shrimp at the opposite end, released a hungry shark, and tracked its movements. Researchers made the hunt more challenging by temporarily blocking the sharks senses one by one and seeing how they reacted.
What they found was nurse sharks did not recognize their prey if their noses were blocked, but the other two did, according to the study. They say smell may be required for nurse sharks because they feed in the dark and suck hidden prey out of small spaces compared to the others which scoop up crustaceans in the day or chase fish at dusk.
When researchers blocked vision, blacktips and bonnetheads could not follow the odor trail, but nurse sharks could.
When the touching sense was blocked, bonnetheads were least able to catch prey. Blacktip and nurse sharks sometimes opened their mouths at the right time if their jaws touched their prey, according to the study, where bonnetheads rely on this because scientists suspect their wide heads allow them to have the special pores that sense electric fields spread across a wider area.
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