Board Thread:Naruto Discussions/@comment-24847491-20140921145042/@comment-5014598-20140922180508

Pretty sure that jugo's transformations are from absorbing the natural energies emanating from different animals, and that the cursed seals and sage modes all use natural energy from different animals (just look at the picture of cursed seal users on the page, and tell me you don't see traits of various animals). Hashirama's Sage Mode definitely has to be slug, its visually similar to the byakugou seal, that has its power directly tethered to Katsuyu. And as for Tsunade and Sakura learning sage mode? Their immense amount of chakra is artificial in nature, I don't think it can be used effectively by them, based on the fact that Minato couldn't do it even though he had access to Kurama's abundant amount of chakra. Then again, it wasn't his chakra, and unlike Naruto, he hadn't melded with it over years and years (or he did, but not in the impure world, and I think time is different in the afterlife). So...