How Does a Crab Eat?

Velvet crab eating blue mussel
Velvet Crab. Paul Kay/Oxford Scientific/Getty Images

Crabs may be a favorite food for some people, but they need to eat too. They often live in dark or muddy areas, where it can be difficult to find prey by eyesight. So how do crabs find food and how does a crab eat? And even more interestingly, what types of food do they like to eat?

How Crabs Find Food

Like many other marine animals, crabs rely on their sense of smell to find prey. Crabs have chemoreceptors that allow them to detect chemicals in the water that are released by their prey. These chemoreceptors are located on a crab's antennae (long, segmented appendages near the crab's eyes that have both chemoreceptors and allow the crab to feel its surroundings and antennules (shorter antenna-like appendages near the antennas that allow the crab to sense its environment). A crab can "taste" using hairs on its mouthparts, pincers and even its feet.

Crabs have pretty well-developed senses of taste and smell. Fishing for crabs, or crabbing, using pots and cages relies on these senses, and makes it possible to catch crabs. The pots are baited with a variety of smelly things, depending on the target crab species. Bait can include chicken necks, pieces of fish such as eel, menhaden, squid, herring, and mackerel. As the bait hangs in the trap in a bag or in a bait jar, odorous chemicals waft out into the ocean, attracting hungry crabs. Depending on water flow, it can affect their senses to detect prey.

What Do Crabs Eat?

First of all, crabs aren't picky eaters. They will eat everything from dead and living fish to barnacles, plants, snails, shrimp, worms, and other crabs -- just to name a few things. They use their claws to grab food particles and put the food into their mouths, kind of the way humans do with their hands or utensils. their claws can also manipulate, or break up, the food so it goes into their mouths more easily in smaller bites. When they have to break through shells of other sea life, their strong claws come in especially helpful while their other appendages help them quickly move to catch various types of prey.

Different crabs like to eat different types of sea life and plants. Dungeness crabs can snack on squid and worms, while king crabs like to nosh on clams, mussels, worms, and sea urchins. Basically, they hunt for prey on the ocean floor and often eat decaying animal matter as well as live sea life.

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