The fastest animals and vehicles are neither the biggest nor the fastest over lifetime.

Journal Article (Journal Article)

Here we show how the size of a body affects its maximum average speed of movement through its environment. The theoretical challenge was to predict that 'outliers' must exist, such as the cheetah for terrestrial animals and the jet fighter for airplanes. We show that during a travel that starts from rest and continues at cruising speed, the body size for minimum travel time, or maximum average speed, is not the biggest. The results are compared with extensive data for military aircraft for chase, attack and reconnaissance, in addition to data for commercial aircraft. The paper also explains why in earlier studies of flying (animals, airplanes) the airplane data deviated upward (toward greater speeds) relative to the theoretical trend followed by flying animals, and why the fastest animal flyers are one thousand times smaller than the fastest swimmers. Unlike the biggest animals and airplanes (elephant, whale, commercial jet), which move constantly, the fastest animals and airplanes spend most of their lives at rest. When judged for speed averaged over lifetime, the fastest 'sprinters' are in fact the slowest movers (as in Aesop's fable 'The Tortoise and the Hare').

Full Text

Duke Authors

Cited Authors

  • Bejan, A; Gunes, U; Charles, JD; Sahin, B

Published Date

  • August 2018

Published In

Volume / Issue

  • 8 / 1

Start / End Page

  • 12925 -

PubMed ID

  • 30150767

Pubmed Central ID

  • PMC6110785

Electronic International Standard Serial Number (EISSN)

  • 2045-2322

International Standard Serial Number (ISSN)

  • 2045-2322

Digital Object Identifier (DOI)

  • 10.1038/s41598-018-30303-1


  • eng