IN THE WILD
The life cycle of the land hermit crab is unique. In the wild, it starts by the release of eggs into an ocean tide pool, where the zoea go through a series of moults and development stages. A baby hermit crab zoea will be a part of plankton until it grows and starts to resemble hermit crab form. Once they have developed to maturity, hermit crabs leave their watery home, making the long journey to land to find a shell for the protection of the soft abdomen.
Once ashore and hermit crabs go through a metamorphosis, developing modified gills that act as lungs to enable them to breathe air. Once on land, they live in a variety of environments including trees, mangroves and areas up to 1-2 miles away from the shore.
In the wild some land hermit crabs can spend a long time away from a water source, some only returning to the sea when they are heavy with eggs which they will flick into the intertidal pools to start the cycle over again. Land hermit crabs are instinctive and will access moisture from dewdrops found on leaves of plants. They are able to go without food for a time if necessary and store water in their shells for drinking later.
In captivity, eggs are deposited in the water source and need to be transferred to a zoea raising set up. For more information about it read the PDF of an article by Stu Wools Cobb, one of the first people in Australia and the world to raise hermit crab eggs to adult land hermit crabs.
Hermit crabs are able to regenerate – or regrow – any lost or broken limbs during the moulting process. Hermit Crabs moult because their hard exoskeleton does not grow with their body, and so they must shed it and infuse the new tissues with moisture, then harden these tissues to develop into an exoskeleton with the aid of ‘chitin‘.
During this time you will need to keep your hermit crab in a comfortably warm and moist environment and offer substrate into which they may burrow within. Some hermit crabs like to dig down deep into the substrate and hide out while their new exoskeleton hardens and they will return to normal activity. For the next 10 or so days heir new skin hardens with the aid of ‘chitin‘ which hermit crabs will obtain by eating their discarded exoskeleton. During this time of natural wonder, you will find your hermit crab is soft, vulnerable, and inactive.
After moulting your crab will need a bigger shell to protect their newly moulted body. Your hermit crab may be a little crabby after a moult and you should offer a variety of shells for them to choose from. Hermit crabs love to size up new shells and will often change shells for hours on end until they find their favourite. For more information on the developmental stages, visit Lesson 3 : Developmental Stages
Underlined words are listed in the glossary. Photo courtesy of Coenobita Species