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Dieren en planten

Decapods   Lobsters   Common lobster   Norwegian lobster   Hermit Crab   Small Hermit Crab   

Hermit crab

size:

up to 35 milliimeters

color:

white with orange to pink tints

food:

carnivores: plankton, worms, small crustaceans, carrion

enemies:

jealous hermit crabs, other crustaceans, fish and some birds

reproduction:

sexual

  • Dut: Heremietkreeft
  • Lat: Pagurus bernhardus
  • Eng: Hermit crab, soldier crab
  • Ger: Einsiedlerkrebs (Bernhardskrebs)
  • Dan: Eremitkrebs
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Hermit crab, Ecomare

Hermit Crab

Hermit crabs have a soft hind body with no external skeleton. They use empty snail shells for protection. They must regularly move into large snail shells in the course of their life. Smaller hermit crabs can be found in periwinkles. Larger ones are often found in whelks. The head, legs and strong claws extend outside the protective shell. As opposed to the small hermit crab, the right claw of the common hermit crab is larger than the left claw. Sometimes, you find the shells covered with a rough substance. Although it looks like algae growth, it is the animal polyp sea mat.

  • Life as a hermit crab

    Hermit crab eggs are carried in the snail shell belonging to the female until they hatch. Her hind legs have grown into fans and provide the brood with fresh water. The young hermit crabs live in the open water for a number of weeks. Afterwards, they look for an empty house from a small snail. After a number of molts, they move into larger shells.

  • Distribution and habitat

    Hermit crabs are found throughout the North Sea. They live in pools and under stones in the lower parts of the tidal zone. Sometimes, large amounts wash up onto the beaches.

  • Various kinds of utensils

    Hermit crabs have an amazing number of ways in which to eat. They have a sieve in their mouth to filter plankton out of the water. They can also extend a slimy net from their mouth to catch these one-celled plankton. The tiny animals which live between the sand grains on the sea floor are caught by sweeping them up with the help of the brushes attached to their mouth. Just like crabs, hermit crabs also eat carrion.

  • Fleeing, fighting and moving

    The hind legs of the hermit crab have developed into hooks with which the animal can anchor itself in the snail house. When in danger, it retracts into the shell. The large right claw is used to close off the opening. It is also used for self defense and for cracking open small shellfish. Some hermit crabs have additional ways to defend themselves. Once in awhile, you may find a hermit crab with a sea anemone on its shell. This anemone scares away enemies. When the crab moves to a new house, it takes the helpful anemone with it.

    Sometimes, hermit crabs fight over an empty or even an occupied shell. Jealousy among neighbors happens with animals as well as humans. Besides neighborly fights, hermit crabs have another problem. There is a lack of large suitable houses, due to the lack of whelks which are the original inhabitants of such a shell. A hermit crab that can't find a larger shell must either remain in its tight house or fight someone else for their larger accomodation.

    When a hermit crab puts its mind into getting someone's else house, it will first take a threatening pose. It holds its claws up high, to show just how large they are. If this doesn't work, it will fight. It grabs the other hermit crab with its claws and begins to tick its house against the other shell in a rhymic manner. Just image your neighbor hammering on your house out of jealousy! It may not sound very heroic, but it often works.

    If the sea mat is sturdy enough, a desparate hermit crab can enlarge the edge of its house using this polyp for protection.