You are More Likely to be Killed by a Coconut*

Whilst you are statistically more likely to be injured by your toilet or by an air freshener, and every year, more people are killed by dogs than by sharks, shark attacks always make the news. Many people still believe that sharks are mindless killing machines and that the risk from sharks is rising. So what is the truth?... Are sharks dangerous? Where do shark attacks occur? And are they becoming more common?

Whilst they have been known to kill people, thousands of divers and snorkelers interact with tiger sharks without incident every year (Image Credit: KARLOS SIMÓN / WikimediaCommons)

How Dangerous Are Sharks?

It is incredibly unlikely that you will ever be attacked by a shark. You are more than 47,000 x more likely to be killed in a car accident! So that means that if you ever cross a road or travel in a car, you are taking a much higher risk than that which is posed by sharks (ISAF).

Compared to many different accidents and diseases, you are incredibly unlikely to be killed by a shark (Image Source: International Shark Attack File)

There are also a plethora of everyday objects that pose more of a threat, including ladders and lawn mowers, which kill more people every year. *Interestingly, the commonly cited idea that your are more likely to be killed by a coconut, is actually a myth. So you need not fear death by flying fruit too much (ISAF).

Statistically sharks also pose much less of a risk to humans compared to many other species of animals. For example, many more people are killed each year by wild animals like hippos and crocodiles, and many more people are even killed by domesticated animals like cows or dogs (ISAF).

We are also far more dangerous to each other than any shark is! You are statistically much more likely to be killed by another human being than by a shark. My all-time favourite statistic (and I swear, this is true!) is that it is more likely that you will be bitten by a New Yorker than by a shark! You can check if you don't believe me, by taking a look at the International Shark Attack File (ISAF).

Great whites are a potentially dangerous species of shark; having been involved in fatal attacks upon humans (Image Credit: Willyam Bradberry / Shutterstock)

Which Sharks Are Dangerous?

The risk sharks pose also varies between shark species. There are more than 540 different species of shark alive today and the vast majority of these are absolutely no threat to human beings. They either inhabit environments it is very unlikely you will ever visit, have teeth which are so small or formed in such a way, that they cause us no real harm, or are very shy and would be more afraid of you than you are of them!

There are several species of sharks which are usually responsible for attacks upon humans when they occur. These include the great white shark (Carcharodon carcharias), bull shark (Carcharhinus leucas), tiger shark (Galeocerdo cuvier) and oceanic whitetip (Carcharhinus longimanus) (ISAF).

Bull sharks, along with great whites and tiger sharks, make up 'The Big Three' species that are involved in the most attacks upon humans (Image Credit: Narchuk / Shutterstock)

Where Do Most Shark Attacks Occur?

These comparatively dangerous shark species are not found at every beach in the world and therefore, the risk of fatal shark attack is very different depending where you are (ISAF).

The highest number of shark attacks each year occur in the USA, Australia and the Republic of South Africa. However, if we calculate the rate of shark attacks in order to account for the population density of a country (that is to say, how many people out of the whole population are attacked by a shark), the Bahamas and New Caledonia have high rates of shark attack compared to their relatively small populations (Midway et al, 2019).

This does not mean that if you are swimming in these countries that you are at risk of being attacked. South Africa and Australia especially have significant beach protection procedures implemented in order to ensure shark attacks remain uncommon.

Shark attack rate (no. attacks per million people) from 1960–2015 in different countries around the world (Midway et al, 2019)

Are Shark Attacks Becoming More Common?

You may have heard that shark attacks are increasing globally... this is because in these reports, you are being told the total annual number of attacks, which does not consider the global population. The population of human beings is growing exponentially every year, so if we calculate how many shark attacks occur as a percentage of how many human beings are alive or how many people are giong into the ocean (known as shark attack rate), we find that shark attacks are not becoming more common and may even be decreasing in some areas (Midway et al, 2019; Ritter et al, 2019; ISAF).

Whilst the absolute number of shark attacks each year has indeed been rising, this is misleading because ocean use is also much higher. When we calculate shark attacks rates per head (shown as 'predicted_rate), it becomes clear that shark attacks are actually declining (Ritter et al, 2019)

A study analysing all shark attack data available up until 2015 found that shark attack rates were not increasing in the majority of countries they assessed. The researchers even found that the rate of sharks attacks has decreased in several areas, including Brazil, Fiji, Mexico and New Zealand (Midway et al, 2019; Ritter et al, 2019). To learn more, you can check out, Myth Busted: Shark Bite Rates are NOT Rising (They're Falling!).

However, this study did report that in some countries - the USA and Australia especially - shark attack rates have risen somewhat since the 1990s. The scientists concluded that this is due to increasing ocean use. More and more people participate in recreational activities in the water in recent decades and therefore, more people come into contact with sharks. This inevitably causes the shark attack rate to rise (Midway et al, 2019).

"Against common assumptions, the world’s shark bite rates are decreasing!"

- Ritter et al, 2019

It is incredibly rare to be killed by a shark - 85% of all people unlucky enough to be bitten by a shark survive the ordeal (Image source: International Shark Attack File)

Do Sharks Kill A Lot of People?

It is important to note that the vast majority of shark 'attacks' are not-fatal. An "unprovoked shark attack" is defined as an incident in which a shark bites a human or their equipment (dive gear, surf board, boat etc.) without bait / chum or other attractants being present. On average, each year 6 - 10 people are killed by sharks globally and in 85% of incidents where a person is attacked by a shark, they live to tell the tale! As our wonderful emergency services continue to advance, we can only hope these figures will improve evn further (ISAF).

Sharks simply are not the great threat that some people believe them to be. In this modern world, where we are becoming ever more aware that we are pose a bigger threat to sharks than they to us, we must put our juvenile fears aside and learn to understand that there is always some risk if we choose to enter their ocean.

Scientists suspect that shark attack rates are declining becasue shark populations have been so decimated all around the world (Image Credit: Gerald Schömbs / Unsplash)

References

Midway SR, Wagner T & Burgess GH (2019). Trends in global shark attacks. PLoS One, 14:2, e0211049. Access online.

Ritter E, Amin R, Cahn K & Lee J (2019). Against common assumptions, the world’s shark bite rates are decreasing. Journal of Marine Biology, Article ID 7184634. Access online.

The International Shark Attack File (2020). Florida Museum. Access online.

By Sophie A. Maycock for SharkSpeak