Size and Strength
Are you stronger than an ant? Trick question. Of course you are, in absolute terms. But an ant can lift 100 times its weight, and--unless you're a circus strongman--hoisting anything that weighs more than about 70 percent of yourself is a big challenge. In a relative sense, the ant is stronger. In general, strength increases with size, but not in a one-to-one ratio. Scientists say strength doesn't scale up with size.
One of the first scientists to write about the lopsided relationship between size and strength was the Italian scientist Galileo Galilei (1564-1642). "I believe," he wrote, "that a little dog might carry on his back two or three dogs of the same size, whereas I doubt if a horse could carry even one horse of its own size."
What's Wrong with this Picture?
You probably don't believe the animal on the left could really exist at the same size as the elephant--and you're correct. For one thing, those legs are too thin to support the weight of the imaginary animal--actually a Grant's gazelle scaled up to Indian elephant size.