I suspect early humans would have been able to make marks on trees to record routes or food caches for millennia before coming up with the more abstract idea of

I suspect early humans would have been able to make marks on trees to record routes or food caches for millennia before coming up with the more abstract idea of an alphabet. This would have been good enough for this task. The earliest cave paintings known are something like 40,000 years old; surely anyone capable of that could come up with a food marking strategy.