by Human fear of sharks has deep roots. There are references in written and artistic works from the ancient world to sharks preying on sailors as early as the eighth century BCE
Back on land, stories of shark encounters have been embellished and amplified. Coupled with the fact that sharks do bite people from time to time – very rarely – humans have been primed for centuries to imagine terrifying situations at sea.
In 1974, Peter BenchleyThe bestselling novel “Jaws” ignited this fear into a wildfire that spread around the world. The book sold more than 5 million copies in the United States within a year and was followed by Steven Spielberg’s 1975 film, which became the highest-grossing film in history at the time. Virtually all audiences accepted the idea, vividly portrayed in the film and its sequels, that sharks were malicious, disloyal creatures that prowled coastal waters seeking to feed on unsuspecting swimmers.
But “Jaws” sparked widespread interest in better understanding sharks.
Previously, shark research was largely an esoteric field for a handful of academic specialists. Thanks to interest sparked by “Jaws,” we now know that there are many more types of sharks than scientists knew about in 1974, and that sharks do more interesting things than researchers expected ever. Benchley himself was a keen advocate of shark protection and marine conservation.
In my own 30-year career studying sharks and their close relatives, skates and rays, there is a growing interest in understanding sharks. This is how things have changed.
Swim into the spotlight
Before the mid-1970s, much of what was known about sharks came from people who went to sea. In 1958, the US Navy established the International Shark Attack File – the world’s only comprehensive database of scientific documentation of all known shark attacks – to reduce wartime risks to sailors at sea when whose ships sank.
Today the file is managed by the Florida Museum of Natural History and the Elasmobranch Society of America, a professional organization for shark researchers. It works to educate the public about human-shark interactions and ways to reduce the risk of shark bites.
In 1962, Jack Casey, a pioneer of modern shark research, started the Cooperative’s Shark Tagging Program. This initiative, which is still ongoing today, relied on Atlantic commercial fishermen to report and return tags they found on sharks, so that government scientists could calculate how far the sharks had moved. after they are tagged.
After “Jaws,” shark research quickly took off. The American Elasmobranch Society was founded in 1982. Graduate students began studying shark behavior, and the number of published studies on sharks increased dramatically.
An increase in field research on sharks coincided with increased interest in extreme outdoor sports such as surfing, parasailing and scuba diving. Electronic tags enabled researchers to monitor shark movements in real time. DNA sequencing technologies have provided cost-effective ways to find out how different species were related to each other, what they ate and how populations were structured.
There was also a quirky side to this interest, which was embodied in the launch of Shark Week in 1988 by the Discovery Channel. This annual block of programming, designed to educate the public about shark biology and combat negative publicity about sharks, was a commercial venture that exploited the tension between people’s deep fear of sharks and their desire for them. understand what made these animals worse.
Shark Week featured made-for-TV stories that focused on fictional science research projects. It was very successful and remains so today, despite criticism from some researchers who call it a major source of misinformation about sharks and shark science.
Physical, social and genetic insight
Contrary to the long-held notion that sharks are mindless killers, they exhibit a wide range of characteristics and behaviors. For example, the velvet belly lantern shark communicates through flashes of light from organs on the side of its body. Perfectly replicating female hammerhead sharks can clone themselves without male sperm.
Sharks have the most sensitive electrical detectors so far discovered in the natural world – networks of pores and nerves in their heads, called ampullae Lorenzini, after the Italian scientist Stefano Lorenzini, who first described these features in the 17th century. Sharks use these networks to navigate in the open ocean, using the Earth’s magnetic field for orientation.
Another interesting discovery is that some shark species, including makos and blue sharks, are segregated by gender and size. Among these species, cohorts of males and females of different sizes are often found in separate groups. This finding suggests that some sharks may have social hierarchies, similar to those seen in some primates and clawed mammals.
Genetic studies have helped researchers investigate questions such as why some sharks have heads like hammers or shovels. They also show that sharks have the lowest mutation rate of any vertebrate animal. This is significant because mutations are the raw material for evolution: The higher the mutation rate, the better a species can adapt to environmental change.
However, sharks have been around for 400 million years and have gone through some of the worst environmental changes in the world. How they managed to do so well with such a low mutation rate is still unknown.
The marquee species
Great white sharks, the focal species of “Jaws,” attract enormous public interest, although little is known about them yet. They can live up to the age of 70, and regularly swim thousands of miles every year. Those in the Northwest Atlantic tend to move north-south between Canada and the Gulf of Mexico; white sharks on the west coast of the USA move east-west between California and the central Pacific Ocean.
We now know that young white sharks feed almost exclusively on fish and stingrays, and that they do not begin to incorporate seals and other marine mammals into their diets until they are teenagers and have has grown to about 12 feet long. Most confirmed great white shark bites on humans appear to be animals between 12 and 15 feet long. This supports the theory that almost all bites by white sharks on humans are cases of mistaken identity, in which humans resemble the seals preyed upon by sharks.
Still in the water
Although “Jaws” had a widespread cultural impact, it didn’t stop surfers and swimmers from enjoying the ocean.
Data from the International Shark Attack File on unprovoked bites by white sharks from the 1960s to the present show a steady increase, although the number of annual incidents is quite low. This pattern is consistent with an increase in the number of people engaged in recreational activities on the coasts.
Worldwide, there have been 363 confirmed, unprovoked bites by white sharks since 1960. Of these, 73 were fatal. The World Health Organization estimates that there are 236,000 deaths per year due to drowning, which translates to approximately 15 million drowning deaths over the same period.
In other words, people are about 200,000 times more likely to drown than die from a great white shark bite. In fact, surfers are more likely to die in a car accident on the way to the beach than to be bitten by a shark.
This article is republished from The Conversation, a non-profit, independent news organization that brings you facts and analysis to help you make sense of our complex world.
It was written by Gavin Naylor, University of Florida.
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Gavin Naylor receives funding from the National Science Foundation and the Lenfest Foundation.
