Hermit crabs are pretty easygoing about what they eat. In fact, they’ll dine on just about anything they can find in the water that surrounds them, including small fish, invertebrates such as worms, plankton and any food particles that happen to be floating by.
Hermit crabs are also high on the list of desired foods for many predators. Fish such as pricklebacks, gunnels, clingfish and snailfish prey on hermit crabs, as do sea stars, larger crabs, gulls and crows.
Aggressive house hunters
Contrary to popular belief, hermit crabs don’t kill the snails in whose shells they make their homes. They’re actually able to “smell” dead or dying snails, which can lead them to a potential shell. But competition for such shells can be fierce. Hermit crabs may fight to the death in pursuit of a shell. And, as they grow, they must seek out new shells in which to live.
Not truly hermits
Contrary to their name, hermit crabs aren’t solitary creatures. In the wild, they’re found in groups of 100 or more. Social behavior in hermit crabs is also sometimes observed during mating, when the male may stroke and tap the female’s claws—or grab her shell and carry her around!—before mating begins.
Hermit crabs are nocturnal, which means they’re much more active at night than they are during the day. To see them scuttling around, visit a Puget Sound tide pool at night during a low tide—be sure to bring a flashlight! You can also see hermit crabs at the Seattle Aquarium, in our Life on the Edge exhibit.