A nice back-of-envelope calculation. Someone posted a picture showing an antelope running through shallow water. Someone else realised that you can use just that single picture to estimate how fast the antelope is moving. The clever bit is estimating the speed of the water waves you can see spreading out from places where the antelope touched down.<p>However, I am unconvinced by some details. For instance, I think s/he overestimated the amount of water wave movement by maybe a factor of 2, the wavelength looks way too large too, and I suspect the water is deeper than s/he assumed. My estimate of the antelope's speed is more like 40mph, which is still very impressive given that it's running through water.