The Collaborative International Dictionary
To run on all fours
All fours \All` fours"\ [formerly, All` four".] All four legs of a quadruped; or the two legs and two arms of a person.
To be on all fours, To go on all fours, or To run on all
fours (Fig.), to be on the same footing; to correspond
(with) exactly; to be alike in all the circumstances to be
considered. ``This example is on all fours with the
other.'' ``No simile can go on all fours.''
--Macaulay.
Usage examples of "to run on all fours".
He felt the urge to hurl the axe aside and use his teeth, to run on all fours as his brothers did.