According to About.com

The total biomass of all the ants on Earth is roughly equal to the total biomass of all the people on Earth.

Is the above statement just a myth or its in fact real? Are there any hard facts to prove this?

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    answers.google.com/answers/threadview?id=536123. it is true it seems... – saiy2k Jan 18 '12 at 6:50
  • Are you skeptical of the paper you present or...? – Sklivvz Jan 18 '12 at 9:20
  • I am not presenting any papers, m just curious to know if its for real – saiy2k Jan 18 '12 at 11:28
  • Ok - the google answers page you just linked contains an answer with a link to a paper. Are you skeptical of that paper too or is it a satisfactory answer to your question? – Sklivvz Jan 18 '12 at 11:35
  • I didnt read through those papers, but I am now convinced that this statement is true.. If I had found that paper before asking here, I would have never posted this question.. – saiy2k Jan 18 '12 at 11:47

Ants drastically outweigh us

If it's good enough for you, the first sentence of Ted Shultz, "In Search of Ant Ancestors," PNAS, December 19, 2000 vol. 97 no. 26, 14028-14029:

Ants are arguably the greatest success story in the history of terrestrial metazoa. On average, ants monopolize 15–20% of the terrestrial animal biomass, and in tropical regions where ants are especially abundant, they monopolize 25% or more.

He gives no reference to a primary source, and that's the closest I can find to a solid reference via the Internet. PNAS is one of the most prestigious journals in the United States, so I think we can trust peer review not to let the opening sentence of a paper be boloney (knock on wood!).

The most likely book I can think of to contain an authoritative discussion is Wilson's The Ants (1990). I don't have it on hand, but it won a Pulitzer, so it's available at many libraries. One part field guide, one part textbook -- if you're interested in ants you should definitely check it out sometime :).

See this table on Wikipedia if you want to pursue more details on human biomass vs. other species. Hard numbers are of course hard to pin down, but the gist is that ants probably outweigh us by an order of magnitude, and termites and krill compete with them for first place.

  • Oops. That's the same paper you linked to in your comment. Foot in mouth :P – SigmaX Mar 12 '12 at 0:43
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    That wikipedia table doesn't seem to say that ants outweigh us. It gives the total mass of humans as 350m tonnes, and the total mas of ants as 30-300m tonnes. Maybe it's changed since you linked. And your quote from Shultz doesn't mention humans. – bdsl Sep 22 '14 at 13:16
  • @bdsl: You're correct. I don't recall what the table looked like when I wrote this answer. But now it indicates that ant mass is at most comparable to humans. JonW's answer should be preferred, since he did in fact trace the claim to Wilson and analyze it. – SigmaX Sep 23 '14 at 13:54

An article recently published by the BBC debunks this myth: http://www.bbc.co.uk/news/magazine-29281253

This claim was originally made by Harvard University professor Edward O Wilson, and the German biologist Bert Hoelldobler, in their 1994 book Journey To The Ants.

They based their estimate on an earlier one by British entomologist C B Williams, who once calculated that the number or insects alive on earth at a given moment was one million trillion.

"If, to take a conservative figure, one percent of this host is ants, their total population is ten thousand trillion," wrote Wilson and Hoelldobler. "Individual workers weigh on average between 1 to 5 mg, according to the species. When combined, all ants in the world taken together weigh about as much as all human beings."

Wilson and Hoelldobler's calculation is based on the idea that the average human weighs a million times more than the average ant. So how well does that stand up to scrutiny? The average adult human weighs 62kg, so that would make the average ant about 60mg.

"There are ants that weigh 60mg, but they're really the big ants," says Francis Ratnieks, Professor of Apiculture at the University of Sussex.

"The common ants which live in British gardens weigh about 1mg or 2mg."

The article there also points out that nobody really knows the actual number of ants in the world:

Experts from the Natural History Museum, Bristol University's Ant Lab, and BWARS (Bees, Wasps and Ants Recording Society), among others, say there is no realistic estimate.

Coupled with the fact that Wilson and Hoelldobler's own calculation is wrong:

Even by Wilson and Hoelldobler's own figures, their calculation is wrong. There are 7.2 billion humans on the planet today - if we take everyone over the age of 15, they weigh a combined total of about 332bn kg. If we imagine there are 10,000 trillion ants in the world, weighing an average of 4mg, their total weight comes to just 40bn kg.

It doesn't seem to hold true that this idea holds any weight. However it was possibly true at one point in history:

"I think if we went back 2,000 years, certainly the ants would've outweighed the humans... but at roughly the time that America became independent [1776], or a little bit before that, that's when we humans became more impressive in our weight than the ants," he says.

"We must also remember that humans are getting fatter all the time. We're not just increasing in population, we're increasing in fatness, so I think we've left the ants behind."

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