What Eats Crabs? 11 Animals That Eat Crabs!

Last updated on October 18th, 2022

What eats crabs? No doubt that this is one of the questions on the mind of every marine biologist.

Crabs are Brachyura infraorder’s decapod crustaceans; their typical little projecting tail is mostly hidden completely under their thorax and their thick mineralized chitin’s exoskeleton covers them.

They have one pair of pincers and are mostly found on the lands and freshwater areas of tropical regions. Freshwater crabs include 850 of their species, and they made their first appearance during the Jurassic Period.

Crabs follow an omnivorous diet, and the large crabs may also eat the smaller ones. They contribute to 20% of the total of marine crustaceans consumed, caught, or farmed worldwide. Here are animals that feed on this crustacean.

Animals that eat crabs:

  • Octopus
  • Hawk
  • Sea turtle
  • Dolphin
  • Heron
  • Seagull
  • Alligator
  • Otter
  • Seal
  • Brown bear
  • Penguin

List of animals that eat crabs:

1. Octopuses

sea urchin octopus and crab 31122021

Octopuses are mollusks grouped in the Cephalopoda class with nautiloids, squids, and cuttlefish in the Octopoda order.

These eight-limbed soft-bodied creatures are bilaterally symmetrical, and at the eight limb’s center, they have one beaked mouth and two eyes.

The octopus’s eight appendages trail behind and they use their siphon for locomotion and respiration. The nervous system is complex, however, they do have excellent sight; octopuses are very clever invertebrates.

Full-grown ones are 15 kg heavy with a 4.3 m wide arm span; the largest discovered octopus species is the giant Pacific octopus.

Octopuses normally consume starfishes, clams, snails, crayfishes, as well as crabs and they are able to catch their prey by paralyzing or killing them with their venomous saliva.

2. Hawks

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The Accipitridae family’s medium-sized diurnal raptors group is named Hawks. These widely distributed creatures range highly in size and kites, eagles, and harriers belong to the same family.

They are capable hunters with sharp vision, and the males are smaller than the females.

Hawks migrate in both the spring and autumn seasons. According to Louis Lefebvre, a Canadian ornithologist’s avian ‘Q’ measuring method, they are very intelligent among themselves and are considered one of the most clever birds.

They feed on small prey like frogs, rodents, grasshoppers, even snails, and sometimes earthworms. They may also eat lizards, snakes, and crustaceans like crabs and crayfish.

3. Sea Turtles

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Sea turtles are Testudines order reptiles belonging to the Cryptodira suborder and are sometimes known as marine turtles. They do not exhibit sexual dimorphism; males and females usually have the same size.

The largest ones are 2-3 m long, 1.5 m wide, and up to 1500 lbs or 700 kg heavy leatherback turtles. Other species are comparatively narrower, and their length varies between 60-120 cm.

Flatback sea turtles eat almost anything from crabs to shrimps to seaweed while leatherback sea turtles feed on invertebrates like sea squirts and jellyfish.

Loggerhead sea turtles are omnivorous and tend towards crabs, conchs, and whelks. Hawksbill sea turtles, usually have sea sponges, shrimps as well as minnows whereas the olive ridley sea turtles feed on jellies, fish, and sea cucumbers.

Green sea turtles are herbivorous and feed on algae and seagrass, and Kemp’s ridley sea turtles prefer crabs strongly.

4. Dolphins

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Dolphins are the Cetacea infraorder’s aquatic mammals, including 40 extant species.

The Maui’s dolphin is around 1.7 meters in length and 50 kg in weight, whereas the killer whale is 9.5 meters in length and 10 tonnes in weight, and this is also the range of their variations in size.

They have torpedo-shaped bodies, bulbous heads, small ears, and long snouts along with necks and bodies that are not flexible.

They show sexual dimorphism, i.e., females are smaller than males, although numerous of their species demonstrate feminine-biases sexual dimorphism, in which the males are smaller than the females.

Dolphins feed on various fishes and squids; these active predators also like having crustaceans like crabs and shrimps. Coastal dolphins prefer having fish as well as bottom-dwelling invertebrates.

5. Herons

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Herons are the Ardeidae family’s long-necked and long-legged coastal and seawater birds, and they belong to the genera Ixobrychus and Botaurus.

They have sixty-four recognized groups; some are referred to as bitterns and egrets. Their beaks are long for evolutionary adaptations.

When they fly, their necks are retracted rather than outstretched, making them differ from the distinct but similar-looking family birds like ibises, storks, cranes, and spoonbills.

These medium-large-sized birds exhibit a little bit of sexual dimorphism and their harpoon-like and long bills can range from extremely fine to thick.

These carnivores tend toward amphibians, reptiles, aquatic insects, mollusks, and crustaceans like crabs. Some opportunistic feeders also artfully eat rodents, snails, and bird eggs.

6. Seagulls

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Seagulls, or formally gulls, are the Laridae family’s seabirds that belong to the Lari suborder. Terns are their closest relative, whereas auks and skimmers are their distant relatives.

These are generally medium-large-sized birds and range from 29 cm in length and are 120 grams in weight. Their color varies from grey to white frequently, with black markings on their wings or head.

They have a cosmopolitan distribution worldwide; they breed on every continent, including the Antarctic margins and the high Arctic.

These ground-nesting carnivores scavenge opportunistically or lay hold of live foods like small birds, fishes, mollusks, and crustaceans like crabs. They eat both dead and living crabs.

7. Alligators

alligator and crab 31122021

Alligators belong to the crocodilian order and Alligator genus within the Alligatoridae family. Chinese alligators and American alligators are two of their extant species, and their fossil remains identify numerous of their extinct species.

A normal American alligator is 4 m long and 360 kg heavy, although they may reach the length of 4.4 m and weigh more than 450 kg.

Chinese alligators are relatively smaller. Usually, they are under 2.1 m and weigh under 45 kg.

Full-grown ones’ color varies from black to dark olive-brown, their undersides are white, and juveniles have white-yellowish stripes that contrast sharply against the dark skin or hides.

These opportunistic feeders, when juvenile, predominantly feed on invertebrates, amphibians, insects, small fish, and crabs, whereas the full-grown ones have snakes, fish, small mammals, birds, and turtles.

8. Otters

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Otters belong to the Lutrinae subfamily; these carnivorous mammals have thirteen extant marine, semi-aquatic, or aquatic species.

Lutrinae is the Mustelidae family’s part, including wolverines, weasels, and badgers. Otters’ bodies are slim and long, with comparatively short limbs.

They have a seal-like ability to hold their breath underwater, and they have strong webbed feet that help them swim. Excluding sea otters, all of them have long and muscular tails.

Otters vary in size from 0.6-1.8 in length and can be 1-45 kg heavy. The Asian small-clawed otter is smaller than any other otter species, whereas the sea and giant otters are the largest.

They mostly eat invertebrates and fish; the giant and sea otter eat crabs as well as crayfish, although they may have individual preferences.

9. Seals

baby seal and crabs 31122021

Seals are mostly marine mammals: carnivores, semi-aquatic, fin-footed, diverse, and widely distributed clades. They have thirty-four extant and over fifty extinct species, described from their fossils.

Their bodies are spindle-shaped and streamlined, their necks are flexible, their heads are rounded, their ear flaps are almost non-existent, and their flippers are modified versions of their limbs.

They can be relatively small, from 45 kg heavy and 1 m long. Apart from the usual fish, their diet contains lobsters, squids, eels, and octopuses; leopards and seals can also prey on penguins and small seals.

The Harbor seals may also eat other invertebrates like crabs whereas the harp and elephant seals are known for consuming krills, squids as well as crabs, and crayfish.

10. Brown Bears

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Brown bears belong to the Carnivora order; they are among its largest terrestrial members found throughout North America and Eurasia.

These large bears are inhabitants of Alaska’s Kodak Islands and thus, also referred to as the Kodiak bears. They are closely relative to polar bears which are a bit bigger on average.

They vary greatly in size, they exhibit sexual dimorphism, and the males are larger with a minimum of 30% in the majority of sub-types.

They also vary in weight for their hibernation; they are lightest in the spring season and the late fall; they are kind of their heaviest version.

These omnivores eat berries, plants, small mammals, and fish like salmon as well as trout and bass. Brown bears that reside close to the coastal regions usually make clams and crabs a regular part of their diet.

11. Penguins

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Penguins are aquatic birds that have adapted to live on land and underwater; this flightless group of birds has flippers that have evolved from their wings and are used for swimming.

They also have counter-shaded plumage for camouflage. A penguin spends one-half of its life on land, while its remaining days are spent underwater.

Their size varies from 33 cm in length and 1 kg in weight. The little blue penguins and the emperor penguins stand 1.1 m tall with a weight of 35 kg.

They usually do not have any special fear of humans. They feed on fish, squids, krill, and even crabs and shrimps, however, different species may have different preferences.

What animals eat crabs?

The animals that eat crabs are octopuses, hawks, sea turtles, dolphins, herons, seagulls, alligators, otters, seals, brown bears, and penguins. Crabs can sometimes move very slowly and this makes them an easy target for these predators.

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