WS MoreOrLess: Mosquitoes and elephants

Summary

More or Less: Mosquitoes and Elephants

BBC Radio 4 World Service | October 7, 2013
Host: Tim Harford
Guests: Dr. Brian Faragher, Ruth Alexander, Rick Smits

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Episode Overview

This animal-themed episode of More or Less critically examines commonly cited statistics about mosquitoes, elephants, and left-handedness. Tim Harford and the team debunk dramatic claims found in popular media and explore the challenges in gathering reliable numbers about the natural world and human behavior.

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Key Discussion Points & Insights

1. Fact-Checking Mosquito-Related Death Claims

• Claim Examined: "Mosquitoes are the most dangerous animal in history, having killed half of all humans who ever lived" ([00:38])
• Public Figures Cited: QI quiz show, Stephen Fry.
• Key Investigation:
  • Previous Analysis: Only 5-10% of all humans ever born are alive today, not 50%.
  • Total Ever Lived: Rough estimate is roughly 100 billion ([00:57]).
  • Current Malaria Deaths: About 660,000 people annually per WHO ([01:39]).

Expert Input

• Dr. Brian Faragher, Liverpool School of Tropical Medicine ([02:11]):
  • "It's very difficult to find the source of it [the claim]."
  • In 1900, about 75% of the world was susceptible to malaria, but only around 1 in 10 who contracted it would die, suggesting a death rate of 4-5% of all humans from malaria even in historical context.
• Tim Harford ([03:13]):
  • Further investigation: Several reputable sources repeat the claim without proof or traceable origin.
  • "[...] the mosquito claim is difficult to prove conclusively, but we don't think it's true."

Notable Quote

• Dr. Brian Faragher ([02:11]):
  "It's probably best to go back to the World Health Organization and look at their statistics for 1900. That was a very important year because there is a lot belief that's around the time when malaria and malaria deaths peaked."

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2. The Data on Elephant Poaching

• Statistic Scrutinized: "96 elephants are killed by poachers every day in Africa" ([04:14])
• Source: Wildlife conservation charity; statistic spotted by listener Graham Marshall.

Key Insights from Ruth Alexander ([04:33]):

• Counting elephants is inherently difficult despite their size.

• Most reliable estimates: Programme called MIKE (Monitoring the Illegal Killing of Elephants) covers 40% of Africa’s elephant population.

• MIKE data: 17,000 elephants killed a year at their monitored sites; extrapolated to a continent-wide figure is about 35,000 per year, or 96 per day.

• Population context ([05:31]):

  • Total African elephant population: 500,000 to 650,000.
  • Annual death rate from poaching: approx. 5%.
  • Uncertainty remains regarding impact, but increasing trends in poaching may soon reduce population numbers.

Notable Moment

• Ruth Alexander ([04:38]):
  • "I know they are big, but they don't like to stride around in the wide open, you see."
• Tim Harford ([05:32]):
  • "But is it a big number?"
• Ruth Alexander ([05:32]):
  • "Well, it's not huge because ...that would mean about 5% maybe a few more are being killed every year now."

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3. Left-Handedness and Crime: A Listener’s DIY Study

• Listener Input: Colin, a former UK police custody sergeant, surveyed 2,000 prisoners and found that 34-36% were left-handed, much higher than the general population’s 9-11% ([06:58]).

Expert Response

• Rick Smits, Author of "The Puzzle of Left Handedness" ([07:36]):
  • Left-handers are "overrepresented in any group that you care to select."
  • This is likely an artifact of data collection methods, not genuine criminal tendency.

Notable Quotes

• Rick Smits ([07:36]):
  • "Left handers are associated with almost anything you can think of: criminality, unlawful inclinations, bad habits, smoking... but also on the positive side: creativity, good leadership, they earn more money."
  • “[...] it's probably an artifact of the way the data are gathered.”
• Rick Smits ([08:28]):
  • "People aren't often all that sure about their own handedness and they don't do everything with the same hand."

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Timestamps for Important Segments

• 00:19 | Introduction & Focus on Animal Statistics
• 00:38–03:50 | Mosquito Death Claims: Origins & Reality Check
• 04:14–06:14 | Elephant Poaching Numbers: Accuracy and Conservation Impact
• 06:14–08:54 | Left-Handedness, Crime, and Data Collection Bias

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Memorable Moments & Quotes

• Dr. Brian Faragher ([02:11]):
  "It's a widely published claim, but it's very difficult to find the source of it."
• Tim Harford ([03:13]):
  "We've discovered that the articles we've been able to access which make the claim don't try to prove it, they just say it."
• Ruth Alexander ([05:31]):
  "So this charity's campaign statistic is probably not far off, I'd say."

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Takeaway

The episode emphasizes the importance of skepticism and diligent sourcing when dealing with widely repeated but poorly supported statistics, especially those that have become media soundbites. From debunking the exaggerated threat of mosquitoes to contextualizing elephant poaching statistics and questioning supposed links between left-handedness and crime, More or Less delivers a careful, accessible exploration of the numbers behind the headlines.

Transcript

[Tim Harford]

Thank you for downloading from the BBC. For details of our complete range of podcasts and our terms of use, go to bbcworldserveys.com podcasts

[Ruth Alexander]

this is the short edition of More or Less, first broadcast on the BBC World Service.

[Tim Harford]

Hello and welcome to More or Less on the BBC World Service. We're the programme about the numbers which surround us in the news and in life. And I'm Tim Harford. This week it's an animal special. We examine the fortunes of elephants in Africa. But first, we're fact checking a BBC quiz show.

[Dr. Brian Faragher]

What is the most dangerous animal in the history of the world? Goldfish. So close. Alan was in fact right. It is the mosquito. Half human beings who ever lived are reckoned to have been killed. 3,000 people die of malaria every day. That's 45 billion human beings in our history. Wow.

[Tim Harford]

Half of all the people that have ever lived. That is a lot of people. Loyal listeners will remember we tried to calculate how many people have ever lived last year to find out whether it was true that half the people who had ever lived were alive today. Not even close. The true figure is something between 5 and 10%, because we think the total number of people who've lived is roughly 100 billion. So have mosquitoes really killed 50 billion people or 45 billion? As Stephen Fry said, we're not going to argue about them, that kind of detail. Well, technically it's not the mosquito that kills, but the viruses and parasites that are transmitted by the mosquito. Diseases such as yellow fever, Rift Valley fever, ross river fever, St. Louis encephalitis, West Nile virus, Japanese encephalitis, they're all mosquito borne, but by far the most serious is malaria. According to the World Health Organization's most recent estimates, 660,000 people are are killed by malaria each year. Now, clearly malaria is not killing half the population at the moment. But what about in the past? I spoke to Dr. Brian Faragher of the Liverpool School of Tropical Medicine in the uk.

[Dr. Brian Faragher]

It's difficult to find evidence to support that claim. It's a widely published claim, but it's very difficult to find the source of it. It's probably best to go back to the World Health Organization and look at their statistics for 1900. That was a very important year because there is a lot belief that that's around the time when malaria and malaria deaths peaked. Now, at the moment, about 40% of the world's population is susceptible to the mosquito and therefore to malaria. Back in 1900, it was just over three quarters of the population.

[Tim Harford]

But would they all have died of it, presumably?

[Dr. Brian Faragher]

No, that's the thing. If you look at the available statistics, again, there's some guesswork involved here, but the feeling is that about 1 in 10 of people who got malaria would die from malaria. And so if you extrapolate that out further and try and work out the total percentage of people who would have died from malaria in 1900, and going back beyond that, it was probably somewhere between 4 and 5%.

[Tim Harford]

Dr. Brian Farragut. Now, the BBC quiz show in question is called qi, and they're fiercely protective of their intellectual reputation. They're not taking this lying down. They say they're in the best possible scientific company because the claim's been made by many reputable scientific sources Nature, the US Library of Medicine, National Geographic and the Wellcome Institute, among others. That's true, but we've discovered that the articles we've been able to access which make the claim don't try to prove it, they just say it. And when they do cite a source to back up the claim, when you follow it up, the trail goes cold. The original source, as our expert from the Liverpool School of Tropical Medicine said, can't be found. So the mosquito claim is difficult to prove conclusively, but we don't think it's true. From mosquitoes to a somewhat larger and more lovable creature, the elephant. 96 elephants are killed by poachers every day in Africa. This statistic was spotted by loyal listener Graham Marshall. It's put out by the wildlife conservation charity. Increasing demand for ivory is fuelling a brutal slaughter of African elephants. They say. Donate here. And fortunately, our resident expert Ruth Alexander, has been looking at the elephant numbers.

[Dr. Brian Faragher]

Ruth?

[Ruth Alexander]

Well, the first thing to say is that counting elephants dead or alive is difficult.

[Rick Smits]

Come on, Ruth.

[Tim Harford]

They're quite big.

[Ruth Alexander]

Well, I know they are big, but they don't like to stride around in the wide open, you see.

[Tim Harford]

Well, fair enough, I suppose. There are poachers about.

[Ruth Alexander]

There are. So the most reliable estimates come from a programme called mike, that stands for Monitoring the Illegal Killing of elephants, and it's run according to a United Nations Convention on Endangered Species. The program has teams monitoring elephants at several sites across Africa, covering about 40% of the continent's known elephant population. They say. Now they reckon that 17,000 elephants a year are killed on their sites, and

[Tim Harford]

their sites cover about 40% of the elephant population. So if you wanted to get to the overall number of elephants killed, roughly double that, you get to 35,000 and

[Ruth Alexander]

35,000 a year, would equate to about 96 elephants a day. So this charity's campaign statistic is probably not far off, I'd say.

[Tim Harford]

But is it a big number?

[Ruth Alexander]

Well, it's not huge because it's thought there are roughly between about half a million and 650,000 elephants in Africa. So that would mean about 5%, maybe a few more are being killed every year now. Does this mean the elephant population is slowly depleting? Well, again, the numbers are uncertain. Five years ago, a study of southern and eastern Africa found that the elephant population was stable in eastern Africa and growing in southern Africa. New research on this is due out soon and the Mike programme researchers are concerned that a recent rise in poaching at the sites they monitor may well be starting to reduce the population of elephants.

[Tim Harford]

Thanks, Ruth. Earlier in the series we discussed the persistent and indeed peer reviewed claim that left handed people die nine years younger on average than right handers. It turned out to be bobbins. Many loyal listeners wrote in to more or [e-mail] including a former policeman, Colin. I hadn't realised the police were listening to the show. I now feel slightly guilty, even though I am of course totally innocent. Anyway, in 1990 Colin served as a custody sergeant in the UK, which means he had direct contact with everyone being brought into the cells as well as those already there. He decided to conduct a little research.

[Colin]

Over 12 months I asked over 2000 prisoners a number of questions which included, is the detained person left or right handed in your program? It was stated that 9 to 11% of the population are left handed. In my survey and this may surprise you, my statistics were between 34 and 36% every month. I'm not sure what this actually tells anyone, but it would suggest that left handed people are more disposed to crime and antisocial behaviour than their right handed counterparts.

[Tim Harford]

Well, I spoke to lefty scientist Rick Smits, author of the Puzzle of Left Handedness and I asked him whether he thought Colin might be onto something.

[Rick Smits]

Well, basically, left handers are associated with almost anything you can think of, like criminality, unlawful inclinations, bad habits, smoking, well, you name it. But also on the positive side, to creativ to good leadership, they earn more money. Left handers always are overrepresented in any group that you care to select. And this is a real riddle why this is so it looks like this can't be true of course, and it's probably an artifact of the way the data are gathered. Take our policeman for instance. I don't think you should put too much thorn in what he got in

[Tim Harford]

data, but it's roughly three or three and a half times more than one would expect.

[Rick Smits]

Yeah, it is. You should take those 9 to 11% with a little bit of salt.

[Tim Harford]

What are the reasons why we might not actually be able to identify people who are left handed?

[Rick Smits]

Well, basically there's two reasons. One is if you ask them the wrong way, they'll give the wrong answer. Don't ask them with hand, they're right because there's cultural pressure there. Don't ask them which hand they eat. Same thing. And the other thing is that people aren't often all that sure about their own handedness and they don't do everything with the same hand. You should look at things like how you sweep the floor, how you strike a match, that kind of simple task. That's why you see the difference.

[Tim Harford]

Rick Smits if there are any numbers you'd like us to take a closer look at, do please email us. Our address is more or lessbc.co.uk and you can also sign up for a free download of our programs at our website, bbcworldservice.com more or less There are dozens of different podcasts now available from the BBC, including news, documentaries, science, business, arts and sport. For details of them all, go to bbcworldservice.com podcasts.