Crab Predators: What Eats Crabs?

Written by Emmanuel Kingsley
Published: March 23, 2022
Image Credit Peterr R/Shutterstock.com
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Crabs make good meals; yes, they do! As much as you would want to have them on your dinner plate, they could be fearful and dangerous to catch. Do you know that the strongest grip from these tiny, hard-shelled decapod crustaceans could crush your fingers? – Woah, that is one hell of a scary feel! Notwithstanding, this shouldn’t change how you feel about these lovely water creatures. Moreover, they are sweet, super old water creatures with many interesting characteristics, some of which include what they eat and what eats them. Let’s learn about crab predators!

Background On Crabs

Sand crab, a Hermit Crab from Caribbean Sea isolated on white background.
There are over 6700 species of crabs in the world and most of them live in the ocean.

Alexander Sviridov/Shutterstock.com

Crabs are any short-tailed members of the crustacean order Decapoda, including the hermit crabs, true crabs, and other forms such as the anomurans. They typically have a short projecting tail hidden entirely under their thorax. They have a flat round body covered by a shell and five pairs of legs with large claws. Crabs can move in all directions.

For their life cycle, the young form of a crab, zoea, metamorphosizes into a megalopa, then to a young crab before becoming an adult. They mostly live within three to five years on average. However, some have lived much more than five years in totality.

There are more than 6700 crabs globally, and most of these crabs live exclusively in the ocean; others live along the shoreline, while some live in large freshwater bodies. However, a handful lives entirely on land but near water bodies. 

Now let’s dive further as we discuss what eats crabs.

What Eats Crabs?

Largest crabs - brown crab
Crab-eating raccoons, turtles, and snakes eat crabs.

Charlotte Bleijenberg/Shutterstock.com

Animals such as fish, birds, crab-eating raccoons, turtles, snakes, sea otters, foxes, shrimp, and humans eat crabs. Some large species of crabs also eat crabs. Despite adult crabs having a solid and hard outer shell, they still make a delicious meal for many animals, but they are most vulnerable to their predators as larvae and juveniles.

Crab Predators: Fish

Great White Shark - Great White Bite
Fish like sharks eat crabs.

Martin Prochazkacz/Shutterstock.com

Many fish species such as sharks, jellyfish, dogfish, cobia, striped bass, red drum, American eels, and many others eat crabs. Smaller fish, sea rays, and eels only attack crabs as larvae and juveniles. Generally, fish mainly feed on blue crabs, especially when the crabs are small or molting (shedding their hard outer shells to enable growth).

Crab predators: Birds

Birds, such as herons, egrets, and diving ducks, eat blue crabs that live in coastal waters and tidal rivers. These coastal birds enjoy eating larvae offshore and young growing crabs on shorelines. Many of these birds use their beaks to carry the hard-shelled crab higher above while smashing it down to break it up. With this unique expertise, these birds have access to the inner parts of the crabs, which serve as delicacies after a hunt. Herons, having the giant, strong, sharp beaks stab crabs and crunch up their shells with their large beaks before swallowing them whole.

Crab Predators: Turtles

Types of pond turtles
Most sea turtles, excluding the green turtle, eat crabs.

dawi88888/Shutterstock.com

Many sea turtles, including loggerhead turtles and the Atlantic ridley, eat crabs, excluding the green turtle, which eats only plants at its adult stage. These types of crab-eating turtles have rigid jaws or beaks mainly adapted for use in crushing and grinding hard-shelled crabs to consume them as food.

Crab Predators: Raccoons

Crab-eating raccoons are omnivores that eat crabs and other crustaceans. They employ their forepaws to tear down the crab and break the shell to reach the inner parts before consuming the meal.

Crab Predators: Snakes

Snakes are predatory animals, and they eat whatever fits in their mouth by swallowing it whole. The cat-eyed water snake (Gerarda prevostiana), a small serpent native to mangrove swamps, employs unique techniques to eat its prey. More astonishing is that they eat crabs five times bigger than their jaws can accommodate. They are picky eaters and often go after soft-shelled crabs.

Crab Predators: Sea Otters

Sea otters hunt mostly hard-shelled invertebrates, including crabs. Sea otters have a unique method to feed on crabs. They dive to rocky reefs and collect a large rock; upon returning to the surface, they float on their backs, with the rocks on their stomachs, and then use the rock to smash their shelled prey to get to the softer parts for consumption.

Crab Predators: Humans

Crabs make a delicious meal for many people around the world. These lovely water creatures are harvested and consumed as food on all continents but not in large quantities compared to fish. People enjoy eating crabs because they are a great source of high-quality proteins containing omega-3 fatty acids (rich in vitamins and minerals), selenium, and many other mineral salts. After removing their hard shell, humans boil or fry the crab with cooking oil to prepare them for a delicious meal.

Crab Predators: Other Crabs

Giant crabs also eat small crabs, especially during a drought. These crabs use their claws to grab and crush smaller crabs before eating. Sadly, female crabs show cannibalistic tendencies as they eat their own young when hungry (although this doesn’t happen frequently).

Other Animals That Eat Crabs

Other animals that eat crabs include:

  • Dogs
  • Octopus
  • Frogs (Fejervarya Carnivora)
  • Alligators

A list of Animals that Eat Crabs

Below is a list of animals that eat crabs:

  • Fish
  • Snakes
  • Frogs
  • Birds
  • Alligators
  • Turtles
  • Fox
  • Raccoons
  • Sea otters
  • Large species of other crabs
  • Shrimp
  • Humans.

How Do Crabs Protect Themselves?

Hard Shell and Tight Grips

Crabs use their hard shells to protect themselves against rocks and predators and have tight grips with their pincers, allowing them to grab and hold off predators and fight them.

Hiding

Crabs take cover under rocks and other objects to hide from predators. Some use seaweed and other plant’s life to cover themselves.

Toxic Algae

Crabs protect themselves from predators by using toxic algae or stinging sea anemones to cover themselves as camouflage to deter predators.

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