Salt is weird. Like, thousands of years ago, salt was super important so much so it was basically currency but it came from the ocean. Specifically salt encrusted rocks...what happy accident was that then?! Some caveman family was at the seaside, one of them accidentally dropped their mammoth sandwich (in that it was big and also made from a mammoth) on one of the rocks and, being an unfussy eater, ate the sandwich then turned around to the others "Okay dudes, you're not going to believe me, but this rock, this one right here, this rock is delicious!" and so, sceptical at first, they all started wiping sandwiches on seaside rocks and found that they loved it.
Or the other explanation is that salty tasting meals exist naturally in...nature...so, ancient humans went on quests to find more accessible salts. Which would be fun to imagine. A caveman scientist, "Day 1, just invented numbers, very happy side effect of quest for salt. Tried licking a porcupine...porcupine seemed to enjoy it, but my tongue did not for varying reasons. Will update log again tomorrow." The next day, "Day 2. Just invented linear concept of time, very happy, though now also somewhat aware of own mortality which is rather uncomfortable. Mission for salt continues, got grandmother to try sucking eggs as per Jeff's suggestion, she said they could use some salt. Will update log again tomorrow." The third day, "Day 3, decided to take a break today with the family, went to the beach. A good time was had by all until Jeff dropped his sandwich on the floor. He caused a scene until I offered to give him my sandwich and I'd eat the one off the floor because it's the stone age and who really cares about germs, apart from Jeff. Found that the sandwich now had salt on it, rocks make salt, fellow salt hunters very happy with my discovery." "Day 4, Jeff suggested salt was actually in the water and that we could harvest it by boiling said water. Crazy Jeff, salt is a solid, not a liquid, he'll never be a scientist like me if he continues to think like that."
I did originally have an ending for this, but I forgot it...so, erm, lets talk about dinosaurs instead. Now dinosaur means "terrible lizards" which is a fantastically inaccurate name as they were neither at all terrible nor lizards. But that is a story for another day, smoke bomb! *flees in confusion*