Starfish, also known as sea stars, are marine invertebrates commonly found across the world’s oceans. They exhibit a star-shaped body with a central disc and usually five arms. Despite their tough exterior, these creatures serve as prey for various other ocean inhabitants, playing a role in the marine food web.
Who Eats Starfish?
Many marine animals prey on starfish, including fish and other invertebrates. Predatory fish, such as nurse, horn, and Port Jackson sharks, consume them. Manta rays, triggerfish, and pufferfish also include starfish in their diets, with some possessing specialized mouthparts or strong jaws to handle the starfish’s tough exterior.
Crabs and lobsters are significant predators of starfish. Crabs, including the large red king crab and smaller decorator crabs, use their powerful claws to break apart the starfish’s body and access its softer tissues. Lobsters also hunt starfish, tearing through their outer armor.
Other invertebrates contribute to starfish predation. Large marine snails, such as tritons, feed on starfish. Certain species of starfish can also be cannibalistic, with larger starfish preying on smaller ones. Specialized shrimp, like the harlequin shrimp, exclusively feed on starfish.
Marine mammals occasionally consume starfish, with sea otters being a notable example, though they often prioritize other prey like sea urchins. Seabirds, particularly gulls, are opportunistic predators, often preying on starfish in intertidal zones during low tide. Gulls use their sharp beaks to penetrate the starfish’s tough outer layer and consume internal organs.
Predator Strategies and Starfish Defenses
Predators use various strategies to consume them. Many, including certain fish and crabs, commonly flip starfish over to expose their vulnerable underside, where the mouth is. Sharks with powerful jaws can crush the starfish’s rigid body, while crabs use their strong claws to tear them into manageable pieces. Some smaller starfish, especially juveniles, may be swallowed whole by larger predators such as manta rays.
Starfish possess several defense mechanisms. Their tough, spiny skin, supported by calcareous plates, provides a physical deterrent. Many species also have chemical defenses, producing unpalatable compounds that make them taste unpleasant. Some, like the crown-of-thorns starfish, are venomous or secrete repellent mucus.
A key defense is their ability to regenerate lost limbs, a process known as autotomy. If a predator seizes an arm, the starfish can intentionally detach it and escape, later regrowing the lost appendage. In some cases, a severed arm with a portion of the central disc can regenerate into an entirely new starfish. Some species also use camouflage or bury themselves in sediment to avoid detection by predators.