We all know pigeons, rats, birds, and squirrels have adapted nicely to city living over the years. And as the world becomes more urbanized and increased development encroaches upon our backwoods and byways, they continue to adjust. So, do we humans. Environmental scientists call those lifeforms that adapt to city living 'urban adapters.' And they call those who don't adapt well, like cougars, bears, and wolves, 'urban avoiders.'
Scientists used to think sharks were 'urban avoiders,' too - until this month when they discovered the opposite: sharks prefer city living.
That's right; these ocean predators have been seeking the city's bright lights, bustling city energy, and cacophony of sounds, but no one knew it until now, say researchers from a study by the University of Miami Rosenstiel School of Marine and Atmospheric Science.
So why didn't scientists know this? Because all previous animal urbanization studies were based on researching land predators, not sharks. Therefore, scientists automatically assumed sharks were "urban avoiders" like their terrestrial-bound counterparts. Admittedly, it's not the most evidence-driven conclusion on the planet, but that was their rationale until the University research team released the new study tracking shark's swimming patterns, proving them wrong.
So, now we know sharks like cities more than we thought they did. But we still don't know why, although the research team has proposed three probable reasons why sharks are attracted to heavily populated Florida coastlines:
nutrient runoffs
sewage discharge
fish discarded into the sea
All of these combine to create a veritable seafood buffet that keeps them lingering close to shore. But, unfortunately, this city-dwelling is not so healthy for the sharks. Scientists are concerned they will become vulnerable to exposure to toxic pollutants that could impact their survival and health for generations.
It is expected that 70% of Earth's population will live in cities by the year 2050, attracting even more sharks to urban coastlines in the future. But this urban migration is a double-edged sword. Sharks are attracted to city life because of the increased feeding opportunities, but urban development also brings the destruction of coastal marine habitat, which is necessary for a shark's survival.
It's quite the conundrum.
Given the increasing urban shark population and the study results, do sharks pose a greater threat to swimmers than before? According to the Florida Museum of Natural History, "No."
The risk of being bitten by a shark remains extremely low, given the number of people entering the waters each year. Still, the United States continues to lead the world in unprovoked shark attacks, and Florida tops the charts with 60% of the total US shark bites. Most of these attacks are related to surfers and those participating in board sports.
The International Shark Attack File (ISAF) offers resources for reducing your risk of a shark bite and instructions for what to do if you encounter a shark and for those interested in learning more.