For some USC professors, every week is Shark Week
Sharks arent just the apex predators we see in movies; theyre complicated, fascinating creatures that Trojans are investigating from many angles.
Most Americans dont think much about sharks throughout the year, save for one week in summer when the Discovery Channel’s Shark Week dominates TV programming.
But some USC researchers spend considerable time studying sharks. They study sharks in marine environments. They study how sharks contribute to modern technology. They study sharks that were contemporaries with dinosaurs. And they study how the hit movie Jaws shaped public perception of sharks as malevolent man-eaters.
Far more sharks are harmless, and have no interest in people, than the apex predators and man-eater sharks that people think about, said David Ginsburg, an associate professor (teaching) of environmental studies in the USC Dornsife College of Letters, Arts and Sciences. At the USC Wrigley Institute for Environmental Studies on Catalina Island, he studies marine physiology, development, ecology and coastal zone sustainability. He also swims with sharks.
[Great] white sharks are probably all over the place in California, but we never see them, theyre not very interested in us, Ginsburg said. Theyre curious, they come up, a fin pops out of the water, they check us out, and most of the time they move on.
However, people take a heavy toll on sharks. Scientists estimate harvesting sharks has depleted many species by an estimated 90% worldwide. Most of the harvesting occurs as shark finning, where sharks are caught and their fins are sliced off to make shark fin soup or other foods. An estimated 100 million sharks are killed by fisheries every year. Many others are killed by nets or long-line fishing gear.
Studying sharks: How their skin has evolved
In the ocean, sharks are apex predators. They are ancient animals, honed by millions of years of evolution into sleek swimming and hunting machines. Indeed, scientists marvel at their adaptations, some of which have been mimicked to advance human technology.
For example, scientists have studied shark skin properties for nearly 30 years. Their skin has V-shaped ridges, or dermal denticles, which serve as a template engineers have used to make sleek, drag-resistant surfaces called riblets thatve been added to vessels and swimsuits.
Mitul Luhar is an assistant professor of aerospace and mechanical engineering at the USC Viterbi School of Engineering. He studies how objects overcome resistance to move through turbulent air or water better. Aided by USC grad student Andrew Chavarin, Luhar developed an algorithm based on shark skin that finds optimal solutions to move things with less friction.
We know shark skin is versatile due to its tiny surface features and aligned grooves. The grooves reduce friction, so a shark expends less energy to swim and go faster. Were transferring those efficiencies into transportation systems like ships and planes. Our system allows us to do this much more quickly with wider application, Luhar said.
We have direct evidence that a shark munched a pterosaur, a flying reptile, about 80 million years ago.
As seen in Shark Week clips, sharks can swim so fast they can propel their bodies into the air to catch prey. Evidently, they learned that trick millions of years ago. Scientists at USC and the Natural History Museum of Los Angeles County found such proof in a fossil.
We have direct evidence that a shark munched a pterosaur, a flying reptile, about 80 million years ago, said Michael Habib, an assistant professor in the Department of Integrative Anatomical Sciences of the Keck School of Medicine of USC and a researcher at the museum’s Dinosaur Institute. Its a super-sized version of predator-prey interaction we see today, when sharks eat seabirds, and its been going on a long time.
Unlike early sharks, which were long and slender, todays sharks are torpedo-shaped. During the Triassic period about 225 million years ago, sharks had V-shaped, fang-like teeth. The biggest shark ever was the megalodon (Carcharocles megalodon), which was roughly 40 feet long and 25 tons with teeth as big as a mans hand; it went extinct about 2.5 million years ago.
How much of our shark fear has been shaped by Jaws?
Sharks inspire awe and fear, the emotions ruthlessly captured in 1975’s Jaws. The film and its thump-thump-thumping theme song indelibly stamped shark terror in generations of Americans.
The music of Jaws was as responsible as filmmaker and [USC Trustee] Steven Spielberg’s imagery for scaring people out of the water in 1975, and continues to be the soundtrack for shark imagery. When you see news about a shark attack, most of us begin to hum the sharks theme, said Jon Burlingame, an assistant adjunct professor at the USC Thornton School of Music. He is a leading expert on music for films and TV, teaching film music history and serving as a consultant for the Los Angeles Philharmonic, the National Symphony Orchestra, the American Film Institute and the Academy of Television Arts and Sciences.
Playing on just a few notes and tempo changes to achieve psychological tension, the Jaws motif ranged from sounds of the deep in the orchestra to the speed of the music itself: loud and fast when the shark was attacking, soft and slow when it was lurking. In each movement, the tone of Jaws music was always menacing. The musics sheer intensity and visceral power helped to make the film a global phenomenon, Burlingame explained.
So, after Shark Week and summer trips to the beach are over, give pause for a moment to reflect on the complex history and biology of sharks and their place in the oceans of our world.