What do Sea Snails Eat?

Quick Take

• One sea snail's venom can kill a human in hours, yet scientists are studying it for something completely unexpected. Explore cone snail venom →
• Some carnivorous sea snails drill geometrically perfect holes through clamshells, and the tool they use to do it is not what you would expect. See how they drill shells →
• Despite their slow, harmless reputation, certain sea snails are apex predators that target fish, and this is how they pull it off. Discover fish-hunting snails →
• With nearly 30,000 species, sea snails occupy every feeding role in the ocean, and a few of those roles are genuinely alarming. See their feeding roles →

Sea snails are gastropod mollusks, characterized by a single coiled shell and a muscular foot used for propulsion. They occupy a wide range of marine habitats, from intertidal zones to deep-sea environments. There are approximately 30,000 species of sea snails, which vary significantly in size, from the smallest, Ammonicera minortalis, measuring 0.013 to 0.018 inches, to the Australian trumpet (Syrinx aruanus), which can be three feet long and weigh up to 40 pounds. Consequently, their diets are highly diverse. Some species are herbivores that eat algae, while others, such as the geography cone (Conus geographus), are carnivorous predators that use venomous teeth to paralyze their prey. Continue reading to discover everything you need to know about what sea snails eat.

What do Sea Snails Eat?

Sea snails eat algae, seaweed, worms, barnacles, carrion, small fish, and other mollusks.

Although most species of sea snails are herbivorous, some are considered scavengers, while others are obligate carnivores, specifically piscivores, that feed exclusively on small fish.

Herbivorous sea snails, such as the marsh periwinkle (Littoraria irrorata), typically eat algae and seaweed. Herbivorous sea snails use a radula, a tongue-like organ covered with thousands of microscopic, tooth-like structures, to eat algae, diatoms, and seaweed.

Carnivorous sea snails prey on living animals, including bivalves like mussels and clams, small fish, sea slugs, other sea snails, and worms, and their hunting methods vary widely.

Lewis’s moon snail (Neverita lewisii) is a carnivorous gastropod that feeds primarily on bivalves like clams by drilling characteristic, perfectly round holes in their shells. These sea snails use a large foot to envelop their prey, then employ their radula and acidic secretions to consume the animal inside the shell.

Considered one of the most venomous creatures on Earth, the geography cone uses its venom-filled teeth to deliver a cocktail of rapid-acting neurotoxins that paralyze its fish prey. The venom is highly toxic and can kill a human within hours. Interestingly, research has discovered that geography cone venom contains insulin-like molecules and other compounds that may inspire new treatments for diabetes.

Scavenger sea snails, such as dog whelks (Nucella lapillus), are opportunistic feeders that consume decaying animal matter, carrion, and detritus found in the substrate. They may also feed on algae, feces, or smaller organisms.

The most common foods sea snails eat include:

• algae
• seaweed
• cord grass
• biofilm
• rotting plants
• small fish
• carrion (decomposing animals)
• worms
• barnacles
• clams
• oysters
• scallops
• other snails
• sea slugs