Why do the fastest insects have 6 legs instead of 2 or 4? Why don't any trot or gallop like a cheetah, for instance?

I know that if a...

  • cheetah were scaled down to the size of a tiger beatle, it would have a higher bl/s bc of decreased air resistance.

  • tiger beatle were scaled up to a cheetah, it would have a lower bl/s bc of increased air resistance.

But shouldn't that encourage the beatle to move like a cheetah at either scale?

  • $\begingroup$ what research have you done on your own? gait is not about optimizing speed but about optimizing efficiency in most animals. Also simple model on a flat surface is largely useless, terrain does not scale the same. also these several very diffrent question you should focus your question more. $\endgroup$ – John Dec 14 '19 at 16:31
  • $\begingroup$ ALL insects have six legs, by definition. The number of appendages, whether 4, 6, 8, or more, has roots far back in evolution. As to why insects move differently from mammals, other than the number of legs, it's a matter of scale. Not many things scale linearly with size. Even among mammals, consider how a small ones like mice & squirrels move differently from large ones. $\endgroup$ – jamesqf Dec 14 '19 at 18:41

Insects have WAY more surface related to their volume or mass than mammals (the surfaces scale as size^2 and the volume/mass scales as size^3). They have to deal with surface-related forces like adhesion, surface tension and so on. OTOH, gravity is less important - up to the point that most insects can walk upside-down.


Moving is complex. Moving efficiently - even more so. A cheetah has part of it's brain that is dedicated to controlling it's movements and it is larger than whatever beetle you can imagine. Insects lack the "computational power" needed to move like a mammal.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.