Sharks seen "adapting" to different environments for first time

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Great white sharks might have more flexible behavior than scientists first thought, according to new research.

After hooking great white sharks up with smart tags, researchers caught a glimpse of the true behaviors of these marine monsters. Rather than stiffly behaving in the same way regardless of context, it turns out that great white sharks are able to adapt their behavior based on different hunting scenarios, according to a new paper in the journal Ecosphere.

Great white sharks are the largest predatory fish in the world, growing up to lengths of 20 feet. They are found in cooler coastal waters off several countries worldwide, including the United States, Canada, South Africa, Australia, and New Zealand. Their diet consists mainly of marine mammals such as seals, sea lions, and small whales, as well as large fish like tuna.

Researchers from Murdoch University, Oregon State University, Stanford University, and California State University Monterey Bay tagged a total of 21 great white sharks of all ages with trackers. These sharks were found in a variety of environments along the coast of California, ranging from islands to shallow waters near the shore. These tags, which measured the location, depths and movements of the sharks, were designed to stay attached to the animals for six days before detaching and floating to the surface

Great white sharks might have more flexible behavior than scientists first thought, according to new research. ISTOCK / GETTY IMAGES PLUS

The researchers then collected the trackers and analyzed the data to find out if sharks behaved the same in all locations or varied their behavior in different environments.

They discovered that sharks were more active during the day than the night at all sites, swimming up and down and twisting and turning about, suggesting that they were hunting for prey. During dawn and dusk, however, they were more active only in places where there was more fish prey than mammal prey present.

"We found the greatest differences in movements were from sharks from different areas, while the size of the shark and time of day were also important," study author Oliver Jewell, a researcher at the University of Western Australia and previous Murdoch University Ph.D. candidate, said in a statement. "This means the sharks are adapting their movements and routines to suit their local environment, rather than behaving the same way everywhere they're found."

Adapting their behavioral patterns allows great white sharks to exploit local feeding opportunities and prey behaviors, the researchers explain in their paper. In some regions of South Africa, Cape fur seals are more vulnerable at dawn, leading to increased shark activity during this time. Conversely, in areas where seals take shelter within kelp forests, sharks adjust by being active throughout the day to optimize their chances of finding prey.

Meanwhile, California made for an ideal location for this study, as it is home to adult and juvenile great whites, and has a vast number of possible habitats for the sharks to pass through.

Adapting their behavioral patterns allows great white sharks to exploit local feeding opportunities and prey behaviors. ISTOCK / GETTY IMAGES PLUS

"White sharks visit the same areas of central California year after year, with some seen in the same spot for 30 years or more," Jewell said. "We were looking to see what shapes their movements and routines while they are there."

The researchers hope that their results and their tagging technology will help shark scientists to better understand these behemoth creatures, and also pave the way for further research into shark behavior.

"Modern technology provides us with unprecedented views into the lives of some of the hardest to study species, in turn offering us novel insights into the functioning of our oceans," study author Adrian Gleiss, a behavioral ecologist at Murdoch University, said in the statement.

Jewell agreed, adding that "hopefully, we can apply the research in a number of ways going forward—we've already been tagging more sharks in more areas, and will follow this up with further studies."

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