Not too big, not too small: Why modern humans are the ideal size for speed

The fastest animal on land is the cheetah, capable of reaching top speeds of 104 kilometers per hour. In the water, the fastest animals are yellowfin tuna and wahoo, which can reach speeds of 75 and 77 km per hour respectively. In the air, the title of the fastest level flight (excluding diving) goes to the white-throated needletail swift, at more than 112 km per hour.