> Sea water would be an easy salt source for any wild animal or human
> livin near a coastline. I think otherwise "salt licks" don't occur within
> easy access of ordinary creatures, in a savannah or anywhere it may *rain*.
>

I read an interesting article recently about African elephants who go
great distances to dig into salty hillsides. Other animals follow them
to eat the salty earth they uncover. There are caves that the
researchers speculate may have been excavated over the millenium by
salt hungry elephants.

I suspect that any animal smart enough to chip stone tools is smart
enough to carry a bag of salt away with him after visiting a salt
lick. Our ancestors could easily have eaten a lot more salt than other
animals for millions of years. Another of those unprovable speculations...