In a beautifully ironic tale, an underwater robot designed to document great white shark feeding behavior has been spectacularly attacked by these fishes, offering scientists the first observations of below surface predatory behavior for the species.
Sure, there’s no shortage of incredible videos of great white shark attacks around – a brief search on YouTube will bring up plenty. But scientists wanted to know more about what goes on below the waves, something that previous studies have neglected. That’s where the Woods Hole Oceanographic Institution’s REMUS SharkCam has come in, an autonomous underwater vehicle (AUV) deployed back in 2013 off the coast of Mexico’s Guadalupe Island.
"Most of what we know about white shark predatory behavior comes from surface observations. We have all seen pictures or footage of sharks surging out of the water to capture a seal," lead researcher Greg Skomal said in a statement. "But we wanted to find out what was happening at depth – when the sharks swam into the deep, how were these animals behaving? Were they hunting? The REMUS AUV was the perfect tool to do this."
During six research missions throughout November that year, REMUS’ recording equipment proved an invaluable tool, helping the team tag and follow four different great whites, one male and three females. One of these is somewhat of a celebrity in the shark world – "Deep Blue," a 5.7-meter-long (21-foot) beast that the team managed to stalk at depths of up to 90 meters (295 feet).
In addition, the camera recorded hours of footage of sharks that the team did not tag, providing a wealth of data for the team to scour through. Of the 30 shark-REMUS interactions documented, some consisted of simple approaches out of curiosity, whereas others involved a bit more attitude. For instance, nine of these events involved aggressive attacks in which the shark attempted to take a chunk out of the equipment.
During these predation episodes, the animal would often lurk deep below the camera before charging upwards in a surprise attack. From this data, the team came to the conclusion that great whites in this area likely exploit the crystal clear waters to search for prey from the dark depths, allowing them to remain concealed and then ambush from below, increasing the likelihood of attack success. You can read more about the team’s findings in the Journal of Fish Biology.
While fascinating, the work’s not over yet: REMUS has already been back for a return trip, the footage from which is due to emerge this summer. The team is also planning on using an upgraded model that can go deeper in future missions, hopefully giving us even more information on the predatory behavior of this magnificent animal.