Mainstream media have often portrayed sharks as vicious predators who eat surfboards and attack humans. While it is true that there are great white shark attacks on humans, a new study from the University of Sydney published on Frontiers in Marine Science suggests that a large chunk of their lives are spent hanging out near the bottom of the ocean rather than on the surface.
Lead author, Richard Grainger said that "the stereotype of a shark's dorsal fin above the surface as it hunts is probably not a very accurate picture."
Scientists studied the stomach contents of 40 young white sharks to get a better idea of where they spend most of their time, LiveScience reports. The data gathered in their research will help future white shark management efforts and understanding why shark attacks happen in humans.
Great White Sharks Are Bottom-feeders
Hands-on analysis of the great white sharks' stomachs revealed its diet. Although about 32.2% of the remains found in the stomachs belong to the mid-water fish like Australian salmon, the bottom-dwelling fish like sole made up a significant 17.4% of the stomach contents. The rest were from unidentified fish.
The remains found inside the stomach of the sharks typically live on the seafloor or buried in the sand, said Grainger. "This indicates the sharks must spend a good portion of their time foraging just above the seabed," he added.
The scientists also found that sharks hunt for bottom-dwelling stingrays, electric rays, and eagle rays, although this can be difficult for the sharks given how fast the latter can swim.
According to CNet, the juvenile sharks Grainger and his team found were mostly snacking on small bites. It is not until sharks reach about 2.2 meters in length that they start hunting for bigger prey such as other sharks and marine mammals like dolphins.
Great white sharks avoid the surface until they’re big enough to scare you https://t.co/iZ6d0nMsst pic.twitter.com/DDvAuV6hA2 — BGR.com (@BGR) June 9, 2020
Moreover, the study also said that larger sharks consume higher-fat diets, which makes sense considering the amount of energy they need.
This fits previous research showing that wild animals select their diet precisely balanced to meet their nutritional needs, said study co-author Professor David Raubenheimer, School of Life and Environmental Sciences' chair of Nutritional Ecology.
Human-shark Conflict
According to a report by Florida Museum, there have been 64 unprovoked shark attacks recorded in 2019. These human-shark conflicts are one reason why understanding the nutritional goals of the great white sharks are important.
The deceased sharks used in the study were caught in nets deployed by the New South Wales Shark Meshing Program, which is made to protect the swimmers in the area, although this can also cause the deaths of some animals.
The scientists clarified in their paper that there are no sharks killed while doing their research.
Study co-author Gabriel Machosky-Capuska said that the study results could help with the species management and conservation decisions of the great white sharks.
It is also a good reminder that movies about shark attacks are only a work of fiction and that these species have more important things to do than trolling shallow waters for humans.
