My entirely uneducated guess would be that its some, very basal, ancient, basically gasping compulsion, that… just never quite fully got patched out by the subsequent tens of millions of years of evolution.
Sort of the behavioral version of vestigal limb, way down at some fundamental nervous system level.
Solitary animals yawn too. Don’t if they can catch yawns, or how to test it.
Supplying oxygen to brain before task, reused in ape for social?
My entirely uneducated guess would be that its some, very basal, ancient, basically gasping compulsion, that… just never quite fully got patched out by the subsequent tens of millions of years of evolution.
Sort of the behavioral version of vestigal limb, way down at some fundamental nervous system level.