While tiger sharks have acute senses of sight, hearing and smell, their home range covers hundreds of square miles, including resource spots outside their sensory range. As bounce divers, they also almost continuously swim between the surface and about 250 to 330 feet below.
"At times these tiger sharks were swimming across a deep channel, open ocean, often at night," Papastamatiou said. "So the question is, 'What are they orienting to in such a seemingly featureless environment?' It really just highlights how impressive their navigation can be."
Researchers determined adult thresher sharks could orient at greater distances than juveniles, most likely because of their advanced development, Papastamatiou said. The study found blacktip reef sharks only traveled randomly, which has to do with their small home range compared to larger areas covered by thresher and tiger sharks.
Papastamatiou speculated the "mental map" the sharks create may have to do with their ability to sense magnetic fields.
"Probably the most interesting sense and still the most misunderstood is magnetic reception," Papastamatiou said. "There is an increasing amount of evidence that lots of, if not all animals, can to a certain degree detect magnetic fields. That is something that could potentially be used over very large distances because there are gradients in the earth's magnetic field and they could use those as landmarks so even swimming through open ocean, which seems featureless to us, may not be featureless to sharks if they could detect these magnetic fields."
He said the research would potent
|Contact: Yannis Papastamatiou|
University of Florida