Captivating Crab Facts: How Do Hermit Crabs Mate?

Hermit crab is an umbrella term for crustaceans of the families Paguridae and Coenobitidae.

A hermit crab is an omnivorous invertebrate. There are over 800 species of the hermit crab in the wild.

Of these 800 species, only about a dozen are land dwellers, the ones that beachgoers are familiar with. Even these are semi-terrestrial, meaning they need access to both land and water to survive. The remaining are all saltwater dwellers. There are only one freshwater species found in Vanuatu, in the South Pacific Ocean, that is an exception. These crabs are peculiar in the crustacean world. They are unlike other crab species because they cannot grow their own shell. They only have a hard shell over their head and the tail end of their body is protected using discarded shells of other animals like snails. In this way, they resemble shrimp or certain kinds of lobsters more than they resemble true crabs. A hermit crab's tail curves into a hook that enables in keeping the borrowed shell fixed to their bodies and carrying it around. Different hermit crabs display different mating behaviors and patterns.

In this article, we hope to quench your curiosity about the mating behavior of the aquatic and land hermit crab with fun and captivating facts about these mysterious animals!

If you like this article, do read up on how do jellyfish reproduce? And how do starfish eat? Here at Kidadl!

Do marine hermit crabs mate in captivity?

A hermit crab does not breed well in a captive environment. Let us explain why.

A hermit crab copulates in seawater, regardless of whether it lives on land or water because the saltwater ensures adequate conditions for the success of the reproductive cycle. This includes optimal temperature and food for the young. A land hermit crab moves towards the shore during mating season, often as part of huge clusters. The mating primarily happens in the water and rarely on the sand. The male crab passes on a sperm pack to the female, which fertilizes her eggs. Upon maturity, the egg is released into the ocean where, upon contact with the saltwater, the eggs bursts releasing the larvae into the sea.

A hermit crab in its larval stage depends on marine plankton for food. They continue living in the marine environment until they mature enough to acquire a shell of their own to protect them on land. They require seawater to keep their gills and stomach moist and help them breathe. The salt in the water is essential for their anterior exoskeleton to grow.

It is not uncommon to see your local pet stores sell land hermit crabs in a pet tank. Or you will perhaps hear stories of people winning a pet hermit crab at the fair. It is important to remember that any hermit crab is a wild creature. Taking them away from their natural habitat can be harmful not just for the individual crab but for the growth and development of the entire species. Hence, breeding hermit crabs in captivity or keeping them as a pet are not sustainable practices.

What season do hermit crabs mate?

Different hermit crabs have different mating seasons. Most species produce eggs and sperms all year round. While some reproduce in summer, others reproduce in springtime. There are some species like the Dardanus deformis that breed the most between August to October. There are also many species that breed all year round. Each hermit crab species has its own unique characteristics and behavioral pattern, which scientists are still studying. There are only some behavioral traits that are common across species, like mating near the ocean and remaining in saltwater during the development stage of the larvae.

The female crab carries her eggs in her abdomen for approximately a month during which time the fertilized eggs change color from red to a dark gray as they mature. This indicates the depletion of the embryo's yolk. Once this change occurs, the crab's gill appendages push clusters of eggs from her pleopods into the salt water for them to hatch.

When land hermit crabs are bred in captivity, summer is generally considered the best time for breeding. However, it is important to create a salt water simulation in the tank with the correct temperature, sand, and rock scenery, and water consistency for the process to be a success. Mind you, perfecting this salt water simulation in a tank to match the crab's requirement can be a difficult process that is often harmful to the pet hermit; the reason why this endeavor is rarely successful. Hence, it is best to leave this to the wild!

Do hermit crabs mate with their shells on?

Most hermit crabs retain their shells during sex. Hermit crab sex does not involve internal fertilization as happens for us humans. However, in order to transfer the packet of sperm called a spermatophore onto the outside of the female hermit crab's body and into her shell, both the partners emerge partially from their shells and place their abdomen together. Many land hermit crab species develop large reproductive organs that allow them to copulate without losing their shells. A lot of mating considerations revolve around the shell including the size of the partner.

The reason why it's important for a hermit crab to hold on to its shell at all times is that in the hermit crab world, borrowed shells are treasures. Hermit crabs always explore opportunities to grab a better shell, one that is lightweight, spacious, and sturdy with a smooth carved-out interior. Such a shell is considered the most valuable. A crab also puts in a lot of effort to erode its shell in the right places so as to create the perfect home for itself. A large enough shell with a comfortable interior allows the hermit crab to grow to a healthy size and explore more storage space for its eggs.

Mating time is perfect for intruding crabs to try and steal the shells from the couple in action. Hence, they need to be extra careful during these times.

Do hermit crabs have to like each other to mate?

Come mating season, hermit crabs take part in extravagant mating rituals like fighting with other hermits to woo a partner. A male crab has significantly larger claws than females which they use to battle for a partner. It is also common enough to see a hermit crab hold the female with one claw and then stroke her with the other. Now while science is still researching the emotional depths of these creatures, the elaborate procreation rituals do indicate that these tiny beings take it seriously!

For hermit crabs, choosing a partner depends on several factors but there are some commonly recurring trends. For example, larger males tend to reproduce with larger females who carry more eggs. Sometimes, smaller males try to copulate with larger females but are often interrupted by larger individuals. More often than not, medium-sized individuals have the most chances of finding a partner. Some land hermit crabs like the Caribbean hermit crab, undertake 3 miles (4.82 km) long treks to reach the shores from the forests and often, copulate on the way. The females then carry the fertilized eggs to the ocean to hatch.

What is it called when hermit crabs reproduce with no mate?

Many aquatic animals have developed the extraordinary capability of asexual reproduction, i.e, reproduction without a partner. However, hermit crabs are not one of them. Hermit crabs do not reproduce asexually. A male and female are always required for breeding to happen.

When ready to breed, female hermit crabs release a pheromone that attracts potential suitors to her. Several male hermit crabs detect this pheromone and approach the source. A fight ensues between the suitors over who completes the breeding. The winner mates with the female, if she is still interested. Copulation can take a few seconds to almost a minute. During copulation, it often seems like the male tries to drag his counterpart out of her shell and kill her, but that is never the case.

Hermit crabs can reproduce their whole lives, although most species tend to breed when young. This is simply because being a small animal in the vast water world is no easy feat! Even with a life span of decades, they often die young because of the dangerous environment they live in.

Although generally tiny, hermit crabs are important creatures who play a vital role in the ecosystem. They are wild animals who thrive near the sea and we as humans should be respectful of that. There are several ways to enjoy hermit crabs without harming their life cycle in an attempt to domesticate them. One of those is reading this article and learning about their reproductive patterns! We hope you enjoyed reading it and learned fun facts about these cute crabs.

Here at Kidadl, we have carefully created lots of interesting family friendly facts for everyone to enjoy! If you liked our suggestions for how do hermit crabs mate? Then why not take a look at what do clams eat or hermit crab facts pages?