Garter snakes have a varied carnivorous diet that includes a wide range of small animals they can overpower and swallow whole. Their typical prey consists of:
- Earthworms, leeches, and other small invertebrates like slugs and snails
- Amphibians such as frogs, toads, salamanders, and newts
- Small fish like minnows and guppies
- Insects including grasshoppers and crickets
- Small rodents such as mice, shrews, and chipmunks
- Smaller snakes, especially juveniles
- Occasionally small birds and eggs from birds, reptiles, or fish
They prefer live prey and will not eat dead or decomposing animals. Garter snakes are opportunistic hunters that adapt their diet based on their habitat; for example, those near water eat more aquatic prey like fish and tadpoles, while those in drier areas consume more terrestrial animals like lizards and rodents
. In captivity, garter snakes can be fed a diet of thawed frozen rodents, earthworms, and feeder fish to mimic their natural diet
