The total weight of all the ants in the world is the same as, if not larger than that of all humans.

Ants are arguably the greatest success story in the history of the animal kingdom. For every human there are about one million ants. In tropical regions; where ants are very common, their weight can exceed that of ground living ‘vertebrates’ (animals with backbones) by up to four times! (PNAS) (The Ants)

For a more detailed look into this amazing ant fact, see the antweb answer.

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