I personally think that hognoses don't have the gape abilities typical of other snakes. Perhaps they don't need the expanding capabilities if they are just eating frogs and lizards. I would also say it is certainly more natural for snakes to eat one large meal rather several small meals. Try a small rat, you don't have anything to lose.
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...the oldest task in human history: to live on a piece of land without spoiling it."
Aldo Leopold (1938)
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us."
Calvin and Hobbes (Scientific Progress Goes 'Boink', 1991)