Crab in the house
A crab in the house is often an escaped pet hermit crab or, along warm coasts, a land crab sent wandering by the rains. Hermit crabs pass homes down the line in size order, and people do much the same.
What it may mean
A crab in the house, away from the tropics, is often an escaped pet hermit crab turning up behind the couch weeks after it vanished. Along warm coasts, from Florida to India, land crabs also wander into garages and kitchens in the rainy season. Hermit crabs have a habit worth knowing. They live in borrowed shells, and when a larger empty shell washes up, crabs on a beach have been seen lining up by size beside it. Once the biggest crab moves in, the next takes its old shell, and so on down the line. Biologists call it a vacancy chain. Human lives run on the same chains: a colleague retires and three people move up, a family buys a bigger house and a young couple gets their first. Most places you fill came free when someone ahead of you moved on, often without learning who came next.
Depending on how you saw it
Crabs set out at a birth
In China, a 1903 encyclopedia says, live crabs were set on the table at a birth and afterward turned loose in the street to frighten away the evil spirits hovering at such times. What do you set out to guard a new beginning in your home?
A hermit crab out of its shell
A pet hermit crab found bare and out of its shell has often outgrown its home or dislikes it, and keepers offer several empty shells so it can choose. When you change homes, jobs or habits, how many options do you let yourself try before choosing?
A crab with a thick shell
The 1903 encyclopedia of Daniels and Stevans held that thick crab shells foretold a cold winter. Crabs do harden a new shell after each molt, and a thick one marks a well-fed crab. What are you thickening your own shell against, and is that winter really coming?
Why it happens in nature
Away from the coast, a crab indoors is most often an escaped pet hermit crab, which can hide for weeks in warm, damp corners. In warm coastal regions, land crabs leave their burrows in rainy seasons and at spawning time and wander into yards and buildings. Hermit crabs must move into larger empty shells as they grow, and they sometimes trade shells in size-ordered chains.
What folk beliefs say
China
At the time of a birth in China, the table was set with cakes and live crabs, which were afterward turned into the street to frighten away the evil spirits that were thought to hover around at such times.
Source: Cora Linn Daniels; C. M. Stevans (eds.), Encyclopaedia of Superstitions, Folklore, and the Occult Sciences of the World, vol. 1 (1903), vol. 1, p. 7. View the page
Madagascar
In Madagascar, children were not to eat crabs, for fear their teeth would decay.
Source: Cora Linn Daniels; C. M. Stevans (eds.), Encyclopaedia of Superstitions, Folklore, and the Occult Sciences of the World, vol. 1 (1903), vol. 1, p. 35. View the page
To reflect on
Whose move made room for yours, and have you ever thanked them?