Every living thing is on one side of the food chain or the other. We eat to live and we live to eat. Crabs are no different from other species. They may seem like simple fellows, just bopping about the seafloor, occasionally molting and breeding, sometimes fighting off intruders, while other times falling in love—but simply they are just trying to live their best life! Surprisingly, their food preferences aren’t as simple as you would think and the other species who prefer them for a meal are diverse.
Keep on reading to discover how crabs hunt, how their environment affects their food choices, what their preferences are, and learn a shocking fact or two that you can use during trivia night or to impress your friends.
To Hunt or Be Hunted
Did you know that crabs smell from their antennae?! Crabs have chemoreceptors located within their antennae that allow them to detect chemicals in the water that are released by their prey. These chemoreceptors also help in determining what prey is worth eating and what they should be attracted to or deterred by. Furthermore, crabs have separate antenna-like appendages close to the antennae that help them to sense their surrounding environment.
Crabs have an excellent sense of taste and smell, which make for great hunters, and their senses help them get away quickly from approaching predators.
Once they come into contact with their preferred meal, crabs can "taste" using hairs on its mouthparts, pincers, and even its feet.
What species do crabs need to look out for so they are not on the bottom of the food chain?
Like most small living things, crabs have multiple predators that they must keep on their radar throughout the day. Taking the Dungeness crab for example, their natural predators include halibut, dogfish, sculpins, octopus, sea otters, and even other species of crab. Salmon also feed on crab larvae.
What species hunt crabs depend on their environment.
According to the Alaska Department of Fish and Game,
“Species which prey upon hard-shelled Dungeness crabs include humans, sea otters, octopus and Pacific halibut; larger Dungeness crabs and staghorn sculpin are important predators on juvenile Dungeness crabs in some areas. In the soft-shell state, they are preyed upon by many additional species.”
And in comparison, looking at the Blue crab, found near the Chesapeake Bay:
“Predators include large fish like croakers and red drum; fish-eating birds like great blue herons; and sea turtles.”
How Do Crabs Eat?
Crabs use their multiple appendages to hunt and eat; and the good news is that they are able to regenerate lost appendages that may be lost due to an injury or in battle with a predator.
The crab experts at the National Park Service describe the three main body parts crabs use to effectively hunt and eat.
- Two pairs (antennae) are for touch and smell.
A number of modified appendages act as a
mouth, used for cutting, picking, sorting and
- The pincers, the most recognizable appendage, are used for grasping, tearing and defense.
Crabs have a wide variety of food preferences; they are not picky eaters. They spend most of their life near shorelines and within reef systems, hunting and catching their food that is carried over by currents and tidal cycles. They typically never go hungry or are in need of sustenance.
Favorite meals on their menu include:
- Sea urchins
- Freshly dead fish
- Even other crabs!
Yes, exactly! Even other crabs.
The Cannibal Crab
Why would a crab resort to eating its own kind if there are plenty of other yummy things to procure?
A species of crab that has no eyes and lives deep down has other food options, yet they appreciate a delicious crab meal as well. Scientists continue to study this species’ behaviors, as they are relatively new on their radar.
Marine biologist Amanda Bates speaks about a recent discovery nearly 3,500 meters deep. The Schmidt Ocean Institute’s research vessel Falkor, which was exploring hydrothermal vent sites in the Mariana region of the Pacific, caught crabs grooming each other and eating bacteria and other parts off one another; and they enjoyed it! Bates likened their behavior to chimpanzees in the wild, picking bugs off each other. During their research, researchers witnessed this species of crab eating one another as well. A strange symbiotic (but not really…) relationship!
Enough about what crabs eat.
What about you? Are you craving a delicious crab meal of some sort? One that you can make in the convenience of your own home?