Animals that eat slugs include ground beetles, ants, firefly larvae, marsh flies, toads, newts, salamanders, snakes, hedgehogs, shrews, moles, nematodes, raccoons, chickens, ducks and songbirds, such as the song thrush. Nematodes are microscopic worms that target and kill juvenile slugs.
The worms enter the slug's body and secrete a chemical that kills the slug. Most animals have trouble eating slugs because of the sticky mucus that encases the body of the animal. However, the hedgehog has developed a means by which it removes the mucus from the slug's body. It rubs the slug in dirt and then brushes the dirt away to remove the sticky film before consuming the slug.
Ants and ground beetles overpower the slug's mucus defense mechanism with sheer numbers. By disregarding casualties, a swarm of ants can eventually overpower a slug's slimy defenses. There are also tropical carnivorous snails, such as the dalmatian predator and rosy wolf snail, that eat slugs.
Gardeners who are seeking a form of natural slug prevention should encourage the slug's natural predators to populate their garden. Installing a small marsh pond to entice toads and other amphibians is just one step toward developing a slug-free garden. Gardeners can also put out citrus peels and melon rinds to bait slugs into concentrating in one area so birds can eat them.