It depends on the species - and the size of the new-born. Most of the commonly-kept species (such as corn snakes or king snakes) will feed on 'pinkie' mice (new-born baby mice). Gradually increasing the size of the 'food' as they get older.
gardner snakes eat dugs and small baby snakes
no
Baby garter snakes will eat small earthworms and live fish or tadpoles.
Baby black rat snakes primarily eat small prey such as insects, small rodents, birds, bird eggs, and sometimes amphibians. They are skilled hunters and use their keen sense of smell to locate their prey. As they grow, their diet will expand to include larger prey items.
sometimes
no
Black snakes are considered a as consumers because they eat meat.
Full-grown rabbits are rather large for most snakes, but many snakes will prey on baby rabbits, and some of the larger snakes can eat adult rabbits.
Garter snakes can eat ants but they are more common to eat other things
maybee
Water
they eat insects when they are smaller but sometimes grow into bigger snakes and start eatine baby mice