Most pet owners want snakes trained to eat mice or rats that have been pre-killed, frozen and freshly thawed. It is the safest and most convenient diet to maintain for a captive snake. However, some snakes refuse to eat mice or rats initially, perhaps because they are not a natural part of the diet. Other snakes may grow bored of rodents or get sick, requiring alternatives.
Snakes that show no interest in eating rodents can sometimes be tricked into trying one if it smells like a different prey, like lizard, for example.
Take advantage of a snake's reliance on smell to identify prey. Choose a prey that is part of the snake's natural diet, be it a snake, lizard, amphibian, fish or whatever. Give a mouse or rat the scent of the natural prey by rubbing the rodent's fur with the natural prey or something that smells like it--shed reptile skin, fish-tank water, etc. For optimal results, freeze the natural prey (or shed skin, fish water, etc.) and rodent together for a day or two before thawing and feeding the scented rodent to the snake.
Once a snake has fed on a few scented rodents, it is often possible to switch them to non-scented rodents.
Alternative natural prey
Some snakes have specialised diets that do not include rodents. Small litter snakes, skinks, anoles or other lizards can be captured and fed to reptile-eating snakes. For fish-eating snakes, fish can be purchased from bait shops or fish farms, or collected from local ponds, rivers or lakes. Fish fillets can be substituted for whole fish occasionally. However, fillets do not provide complete nutrition and are not recommended for long-term use.
Amphibian specialists can sometimes be fed salamanders purchased from bait shops, but generally frogs and toads must be collected wild for use as captive snake food. Toads and some salamanders can be toxic, so it is important to ensure that a pet snake is adapted to physiologically handle the toxins of a given species.
Strictly insectivorous snakes--such as rough green snakes (Opheodrys aestivus) and wormsnakes (Carphophis spp.)--can be fed, crickets, earthworms, and nightcrawlers purchased from bait shops and cricket farms.
Manufactured "reptile sausages"
Reptile "sausages" are available that are designed specifically for carnivorous reptiles and pet owners who dislike feeding animals live or frozen prey. The sausages--made of processed beef, flaxseed mill, collagen, and a number of vitamin and mineral supplements--are available in four sizes and are purchased frozen.
Pinky pumps are basically large syringes that liquefy newly-born "pinky" mice and force the liquefied pinkies through a tube into snakes' stomachs. According to David and Tracey Barker--experts on snake breeding and husbandry, and owners of Vida Preciosa International, Inc.--pinky pumps are used to force-feed hatchling snakes that prefer a lizard diet, but will begin eating rodents after an initial growth spurt. Pinky pumps are also sometimes used to nourish non-feeding snakes for extended periods, but are mainly designed for snakes that weigh eight to 20 grams.