Scrat won't find the golden nut here, but he'll find several walnuts that'll help him pass in several locations and one of them being: the place where the Fire God shall be killed. And the supposed-to-be Fire God is: Sid.
If you had asked like this: 'Why you not talk to the sloth?' I would have answered to you, but in this case, no. Consider it a lesson of manners, dumb ass!
PS2 (Double jump, then press square) Xbox (Double jump, then press X) Wii (Double jump, then flick the Wii remote down) Gamecube (Double jump, then Press B)