the main reason is that everything within physical reality reduces to the
one-way flow of energy from order to disorder that is what's described by 2nd
our nervous systems 'climb' the energy gradient that is wdb2t. the get-up that
'climb' most-efficiently can survive relatively better.
within this 'equation', big bodies require comensurately-big nervous systems
be-cause they have to signal longer distances within that bigger body, which
means that neruons have to be larger so that they can contain larger versions
of the energy-transformation stuff that empowers neural activation dynamics.
it's a trade-off that's within the equation, because there are many ways to
optimize survival, but some require the performance of relatively-more
externally-relevant work than do others... 'no problem', build a body that's up
to doing the work in that niche of the environmental spectrum. it can still be
relatively well-optimized with respect to wdb2t.
i'm reminded of Jesus' saying: "In my Father's House, there are many mansions."
this stuff, with respect to brain-size, and 'what that means' re so-called
'intelligence is 'just' a 'PC' form of 'chauvinism' that's "built on sand", so
it's worthwhile to not get caught-up in-it.
cheers, ken (K. P. Collins)