Humans have exceptional capabilities to run long distances in hot, arid conditions. These abilities, unique among primates and rare among mammals, derive from a suite of specialised features that permit running humans to store and release energy effectively in the lower limb, help keep the body's center of mass stable and overcome the thermoregulatory challenges of long distance running. Human endurance running performance capabilities compare favourably with those of other mammals and probably emerged sometime around 2 million years ago in order to help meat-eating hominids compete with other carnivores.