[GarterGuy]

I think when it comes to garters, as long as they're not overfed (as snakemanhad said) rodents can make up a large percentage of if not all of their diet. They're not the first non-rodent eating snakes to be raised on all rodent diets. Many of the kingsnakes and milksnakes (Lampropeltis sp.) that are kept and bred now are actually other reptile eaters (lizards and other snakes) and western hognoses (Heterondon nasicus) that feed primarily on frogs, toads and lizards have been raised over many generations on rodent diets. For me, it's a primary rodent diet, just because of ease and the assurance that the food item is healthy and free of parasites.....but I also like to offer them variety, mixing in home raised earthworms, fish (whether whole or fillets) and now I can add canned snails to that. I think what it comes down to is that many snakes can be considered generalist who specialize. What I mean by that is that they can and will eat just about anything, but due to the environment they live in and the other species with which they are competing with, they specialize in certain prey items. In captivity, they don't need to do this and can be given prey they normally wouldn't eat in the wild. Just my little swing on the whole thing.
Roy