PROBABILITY & PERCEPTION (WITH ADDED SHARKS)

staffy teeGiven how much I detest dogs, you may be surprised that I’m writing another post about them.  Dogs.  And sharks.  Because that’s the next logical step, yes?

Anyway, the inspiration for this post comes from something I saw posted on Facebook – this t-shirt (right):

And this got me thinking – which would be more dangerous (assuming that the shark could somehow survive being taken for a walk on a lead)?

How many deaths per year can be attributed to dogs?  And to Staffordshire Bull Terriers in particular?  What about the number of shark-induced deaths?

Well this is a tricky one to answer, not because the stats aren’t available – they are – but because we need to define the problem properly.

If we only consider the UK, there aren’t a lot of shark attacks.  According to The Shark Trust, there have only been two unprovoked shark attacks in British waters since 1847.  So dogs would appear to be more likely to cause you injury in that case.  And the figures back it up: During the last five years, 17 people in the UK have been killed as a result of being attacked by dogs, and there were 6302 hospital admissions in 2012 – 2013 from dog attacks.

But what about worldwide?  There are certainly a lot more sharks in other countries, but there are also different laws and cultural norms governing the keeping of dogs.  Add to this the fact that in other parts of the world, diseases like rabies are prevalent, and the question becomes more complicated. This page from worldmapper gives data on the number of deaths from rabies worldwide.  Most human deaths from rabies can be attributed to dog bites, but the page doesn’t give an actual figure for this – maybe it is difficult to attribute all deaths from rabies to a particular cause,or maybe the data is not well-kept: According to the US Centers for Disease Control & Prevention, in many countries where rabies is more common it tends to be under-reported but that 99% of human deaths from rabies can be attributed to exposure to rabid dogs.

Well, that’s an awful lot of rabies deaths from dogs. The WHO reports that globally around 55,000 people die every year from rabies, and 99% of that is 54,450.

What about attacks from dogs per year, globally? The WHO state that they just don’t know the precise number of people attacked by dogs every year, but it is estimated to be in the tens of millions. Statistics on deaths caused by dog attack are just as hard to find, but it is estimated that in the US up to about 20 deaths per year can be attributed to dog bites, with similar figures for other developed countries. In the US, approximately 4.7 million people will be bitten by a dog annually, and only 0.0002% of those people will die from it.

So let’s take the wildly imprecise figure of ‘tens of millions’, call it 50 million, and multiply it by 0.0002% – this gives us 100 deaths from dog bites worldwide, but as previously mentioned, this figure might as well have been plucked out of thin air. It might be more, it might be less. But it isn’t many. It seems that in countries where rabies is rare or non-existent, you are very unlikely to die as a result of canine activity. In a country where rabies is a problem, you have a better reason to be more wary of dogs.

So let’s look at the total number of shark deaths worldwide. In 2013 there were 72 recorded unprovoked shark attacks on humans. 55000 is sure looking a lot bigger than 72.

But let’s get a bit of perspective. Being attacked by either a shark or a dog is a terrifying thought, but it is pretty unlikely to happen to you. In the UK you do have a virtually zero chance of being killed by a shark, but also only a 0.01% chance of being bitten by a dog in any given year. Dog attacks make for great newspaper stories, but we never hear about the many thousands of cases where a dog was perfectly well-behaved and injured no-one.

Worldwide the story is a little more complicated; your chance of dog-induced death depends on where you live, whether rabies is a problem there, and what your country’s healthcare system is like. However, there are plenty of things that are far more likely to kill you, such as cows and bees, an every year the newspapers run a story quoting statistics from RoSPA, with at least a smattering of human-interest-comedy-anecdotes to make it more readable (and hence, less boring). Did you know for example, that in 2002, 11,500 people in the UK were admitted to hospital with injuries sustained while trampolining

And don’t forget, that most accidents occur in the home. Statistically, you’re safer going for a swim in shark-infested waters (I’m really not advocating this).

Maybe one of the more interesting aspects to this is why we find certain animals and certain breeds of animal so scary in the first place, and why we would happy carry out relatively risky day-to-day activities without a second thought. Compared to the chances of other disasters befalling us, what is the risk really like? The reason why we are frightened of, say, dogs or sharks, is (apart from over-zealous media reporting), that these incidents happen frequently enough to be aware of some level of risk. Using the example of being struck by lightning, you have a 0.0003% chance of this happening to you. But multiply the global population of 7.186 billion by 0.0003% and you get just under 24000 people. Which is a substantial and visible number. Like Terry Pratchett said, “million-to-one chances crop up nine times out of ten“.

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