Ivysaur appears to be based primarily on some form of
reptile, specifically mammal-like reptiles known as
Dicynodonts from the
Permian period. Along with visible ears and no genuine metamorphosis stage (evolution aside), Ivysaur appears to have more in common with
mammals than
amphibians like
frogs and
toads, which metamorphose from one definite creature into another as they mature as opposed to just growing into a larger adult version of itself the way that Bulbasaur does. Alternatively, Ivysaur's large rounded snout, wide mouth, wide-set eyes, blotch-patterned skin, and quadraped-like movements are vaguely similar to those of certain amphibians, such as the
common toad. Unlike Bulbasaur, Ivysaur's "ears" do have hollows indicating that they are in fact ears and not glands, as seen in many species of frogs and toads.
The bulb on its back now resembles the bud of a genus of parasitic flowering plants known as
Rafflesia.