Well actually your creatures are migratory so you do move about a bit early on lol. And the snailfarm evidence they found was prehistoric (such a massive area of time lol) And is the first evidence of agriculture of any sort found. However fire was probably earlier, though i have no idea on the earliest evidence of manmade fire. (i dont remember ever seeing carbon diposits you'd expect from a fire next to prehistoric cave carvings when i've seen them on tv
, but its not exactly like i've been looking for it lol.