Earth’s Land Mammals by Weight

(Randall Munroe/xkcd) 

Cattle that tip the scales against us. Unfortunately for cows, they never mastered the barbecue arts and shall remain our subordinates.

I find it interesting that the weight is carried so overwhelmingly by domesticated mammals.


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The title says "land mammals", which excludes whales and dolphins. Most of the animals in the woods are not mammals. I included rats in my earlier analysis. There are several times more mice than rats, but they are smaller.

There are under 100 million kangaroo. At under 20 kg each, that gives at most 2 squares. There are as many sheep in Australia as kangaroo.

If you do a mouseover, Randall points out that bacteria overwhelm us by mass by 1000-fold, even excluding the several pounds of bacteria in each of us. Speaking of ants, there are many times more ants by mass than humans. For some more definite numbers, see http://en.wikipedia.org/wiki/Biomass_%28ecology%29 . There's also grasses, trees, and corals in the ecosystem, if one wanted to include all species.

There are 4 billion tons of humans that can fit in a cubic mile, if mushed together. That picture shows that there's only 358 million tons of humans, so yet, we easily fit into that cube. But describing the size of a cube is little different than giving the total mass. The raccoon cube, for example, would be a lot smaller.

You are free to feel skeptical. It's best to back up that skepticism with numbers. The numbers I've been able to find back up Randall's chart. A more complete chart, which included all species, would need to include the millions of acres of foodcrops.
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What about kangaroos, wild life in Africa, whales (876,000 according to Wikipedia lower end estimates) , dolphins (wiki answers 170,243,000 - if you assume that an average dolphin weighs 3 times an average human that is ~10-13% of humans by weight), small animals everywhere, etc.
There is a LOT of earth and if you have ever sat still in the woods you will quickly notice there are a LOT of animals. I have read that all the humans in the world would fit into one cubic mile http://www.democraticunderground.com/10023735915
I am always skeptical of these types of pronouncements. Here are some other good videos that actually give you the science behind their statements http://overpopulationisamyth.com/overpopulation-the-making-of-a-myth

I love XKCD but I am not sure this is a good analysis. The world is just too big and we (people) seem to overestimate our size and impact in the world. While we see people around us everywhere we look we are like ants in an anthill saying that all we see are ants. There is a lot of the world that is not anthills
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My attempts at checking the numbers suggests that Randall is right.

One site says there are about 30 million deer in the US. Assuming they weigh about 40 kg each, that's 1 square. (Adult whitetail are heavier. I'm trying to include the young.) Another site says there are 15 million roe deer in Europe, but they are about 20kg each. Deer certainly count for at least 2 squares on the chart, and likely 4 or 5, but not much more.

There are some four billion rats in the world. At 0.5 kg each that would be 2 squares. I haven't found a good count of the number of raccoons in the world. Most of the state and province reports I found report around 1 million, so I'll say 100 million at the upper bound. At 5kg each that's 1/2 a square. In any case, there are more dogs and cats than raccoons.
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