Over 6,000 different kinds of crabs live all over the world. They spend most of their lives on the ocean floor with other sea creatures. The Japanese spider crab is the biggest and most dangerous crab. Its legs are 9 to 12 feet long, from the pitcher to the pincher, and it can grow to be as long as your hand.
Most crabs can also be found on the worlds coastal, shore, freshwater, and river areas. Each of them may be different from the others, but they do have some similarities in their diet. If you want to know what crabs eat in the ocean, we will list each one below.
With their large claws and hard, protective shells, crabs are fascinating creatures that inhabit coastal waters and seafloors worldwide. There are over 4,000 species of these ten-legged crustaceans. But when it comes to their diet, crabs aren’t too picky about what they eat.
In this guide we’ll explore the omnivorous appetite of various crab species. You’ll learn what crabs like to eat, how they hunt and scavenge for food, how much they eat and more. Let’s dive right in!
Key Takeaways on the Crab Diet:
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Most crabs are omnivorous eating both plant and animal matter.
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Small fish, shrimp, dead animals, algae and more make up the crab diet.
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Their main food sources provide protein, vitamins, minerals and healthy fats.
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Crabs use their claws and senses of smell and taste to find and capture food.
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They are scavengers and predators, eating both live catches and dead organisms.
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Meal size is small due to their mouth anatomy. They nibble frequently.
What Do Crabs Like to Eat?
Crabs will eat just about anything they can get their claws on! Here are some of their favorite foods:
Small Fish
Fish make up around 10% of the diet for larger crab species. Crabs nibble on dead fish they find on the seafloor, as live fish tend to be too quick and agile for them to catch.
Shrimp, Prawns & Krill
Shrimp and other small crustaceans are tasty, nutritious snacks for crabs. They provide important nutrients like omega-3s, protein and calcium.
Dead Animals & Carrion
Crabs aren’t the best hunters, so scavenging dead animals is an effective feeding strategy. It allows them to get nutrients from decaying matter with minimal effort.
Crustaceans
Some crabs will eat smaller crustaceans like crayfish, barnacles and even other crab species. The hard shells provide vitamins and minerals.
Squid & Whelks
Large crabs like the Dungeness prey on squid and whelks. These animals contain higher protein than other options.
Clams & Mussels
Clams and mussels offer crabs a boost of vitamin B12 and omega-3s. Larger crabs can crack open their shells.
Seaweed & Algae
For smaller crabs, seaweed and algae provide an abundant vegetarian food source. Algae offers vitamins, minerals and aids molting.
How Do Crabs Hunt for Food?
Crabs aren’t equipped with the best vision or speed for hunting, so they’ve adapted unique food sourcing strategies:
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They use their sense of smell via chemoreceptors to detect prey nearby.
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Once they smell appealing chemicals, they use their claws and legs to pin down food.
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Larger claws can crush thick shells and exoskeletons of animals like whelks.
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They scavenge by sifting through sand and debris for uneaten scraps.
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Some collect algae by delicately scraping or cutting pieces off rocks.
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They may work in groups to secure larger food sources.
Why Can’t Crabs Take Large Bites?
Crabs don’t have teeth and lack powerful jaws. So they can only take very small bites of food at a time. Their hard shells and mouth anatomy make it tough to break down large pieces.
Nibbling small bits prevents crabs from choking. It also allows them to better taste for toxins or spoiled food. This is why crabs are frequent grazers, eating tiny portions throughout the day.
How Much Do Crabs Eat?
On average, crabs only need to eat two small meals per day to meet their nutritional requirements. They have slow metabolisms and don’t move around a ton, conserving energy.
You won’t see a crab gobbling down a whole fish fillet in one sitting. Just little bite-sized bits are sufficient at each feeding time. Their frequent mini-meals allow them to get all the macro and micronutrients they need.
Why Crabs Play an Important Role in Their Ecosystem
The crabs’ diverse diet makes them a key organism in maintaining the health of coastal marine habitats. Here’s how they contribute:
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As scavengers, they pick ocean floors clean of decaying matter that could spread disease.
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Their consumption of algae helps prevent excessive algal blooms.
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As prey for larger species, they provide nutrition up the food chain.
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Burrowing crabs aerate sediments, allowing oxygen and water flow.
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Their discarded shells provide housing for hermit crabs and other animals.
So although they are not at the top of the food chain, crabs help stabilize the intricate balance of coastal ecosystems. Their eating habits directly and indirectly support other aquatic life.
Can Crabs Be Vegetarian or Vegan?
Some crab species can survive on non-meat foods like seaweed and algae alone. However, most crabs are omnivores and need at least some animal protein to stay healthy.
A fully vegetarian or vegan diet would not provide sufficient nutrition for most crabs in the wild. But pet crabs can potentially get necessary protein from formulated vegan pellets or chows.
Unique Dietary Adaptations in Different Crab Species
Not all crabs eat the exact same diet. Certain species have fascinating dietary adaptations:
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Coconut crabs climb trees to eat coconuts, fruit and other terrestrial foods.
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Spider crabs have tiny hooked mouthparts specialized for straining plankton.
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Yeti crabs have claws covered in thick bacteria mats they use to “farm” their food.
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Pea crabs live symbiotically inside mussels and clams, eating their host’s food.
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Teddy bear crabs grow sponges on their claws to collect tiny organic particles to eat.
From algae-eating marsh crabs to fish-hunting king crabs, dietary diversity allows crabs to thrive in many ecological niches.
Favorite Crab Recipes That Showcase Their Sweet Flavor
After learning all about the crab diet, you’re probably craving some of this delicious crustacean yourself! Here are some mouthwatering recipes that highlight crab’s succulent texture and natural sweetness:
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Crab cakes – Lump crabmeat blended with breadcrumbs, egg, and seasonings, then pan fried.
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Crab salad – Flaky crab mixed with veggies, mayo, lemon, and herbs.
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Crab dip – Hot and cheesy blend of crab, artichoke, spinach, and Parmesan.
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Crab legs – Steamed or boiled snow, king, or Dungeness crab legs, served with melted butter.
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Crab imperial – Lump crabmeat baked with cheese, butter, sherry and spices in the shell.
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Crab pasta – Fresh crab tossed with spaghetti or linguine, garlic, olive oil, parsley and red pepper flakes.
So put that bib on and get cracking on some succulent crab recipes! Just avoid eating crabs raw or undercooked to minimize risk of illness. Now pass me the crab mallet, it’s time for a feast!
Bottom Line on the Crab Diet
Understanding the crab diet provides a fascinating glimpse into their biology and connections to marine ecosystems. Whether eating kelp or critters, crabs help keep ocean life in balance.
What do Crabs Eat?
Crabs are omnivorous creatures. Some eat a diverse diet consisting of seaweeds, worms, shrimp, algae, and many more. Larger crab species tend to have a diet consisting of crabs, mussels, small fishes, and squids.
Some species of crabs can also take down hard foods such as barnacles, sand dollars, and even starfish. What a crab eats depends on what kind of crab it is; some species only eat meat, while others eat both plants and animals.
Crabs’ Way Of Hunting?
What do crabs eat in the ocean? To answer that question, you must first know how to hunt, because that’s how they get their food, right? Depending on their size, they mostly eat smaller crabs, crustaceans, and other small fish.
To give you an example, the Dungeness crab does best when it’s cold outside, and it will eat almost anything, like worms, starfish, crabs, squids, and so on.
Some other crabs also eat fish, eggs, snails, or even eat their kind if need be. There are other types of crabs that hide out on land and eat plants, small birds, and dead animals. Scavenging crabs can eat about any dead matter settling on the ocean floor or inland.
What do crabs eat?
What do crabs eat in the ocean?
In the ocean, crabs have access to a wide variety of food sources. They will typically eat algae, plankton, mollusks, and small fish. Some species of crab even have a symbiotic relationship with certain types of algae; the crab will eat the algae and then excrete it back into the water, providing nutrients for the algae to grow.
Are coconut crabs healthy to eat?
Crabs are rich in omega 3 fatty acids, protein, vitamins like riboflavin and minerals like selenium, copper, phosphorus. Coconut crabs are not known to be poisonous. The fat in the abdomen and the egg inside the female are the delicious edible parts. It is prepared by steaming or boiling them in coconut milk. Consuming coconut crab along with sea mango, cerbera manghas may make the coconut crab toxic due to the presence of cardiac cardenolides(cardiac active steroids). This causes electrolyte imbalance that affects the electrical conductivity of the heart.
What do pet crabs eat?
Yes, crabs can eat vegetables like lettuce, carrots, and fruits like banana, apples, and berries. How Often Should I Feed My Pet Crab? It is recommended to feed your pet crab small amounts twice a day, or larger amounts once a day. Overall, understanding what crabs eat requires research and attention to detail.
What do freshwater crabs eat?
Freshwater crabs are typically omnivorous, eating both plant and animal matter. In the wild, they will scavenge for food, eating anything from algae to carrion. They may also eat insects, small invertebrates, and even fish!