Today we are going to talk about an animal that has the ability to take its home literally wherever it wants. Its about hermit crabAlthough they are crabs, they are more closely related to lobsters than to crabs. other marine crabsThey don't have a hard shell like other animals, but they do have a shell that serves to protect their body. The curious thing about this animal is that, as it grows, it uses empty sea snail shells for protection. Its life consists of searching for more comfortable homes as it develops and They're too small for her.
In this article we are going to tell you how the hermit crab lives and what are its characteristics.
Key features
The hermit crab is also known as a soldier crab. It is a crustacean that belongs to the decapod family and There are about 500 species of these crabs all over the world. Although most hermit crabs are aquatic, there are also some species that are terrestrial.
It uses the shells of snails or other mollusks to cover its abdomen, as it lacks a carapace like other crustaceans. It is softer and, therefore, most vulnerable to possible predator attacks. You could say it's a scavenger species, but it doesn't feed on the carcasses of other animals; instead, it uses the shell to live in them.
You can usually Watch it strolling along the seabed, eating and growingIf there's a dead snail along the way, this animal will leave its old shell to adapt to the new, empty one. This only happens if the new shell is more comfortable than the old one. If it finds a smaller shell, it won't take it. This natural adaptation is preventing it from evolving and developing its own shell. By always choosing another animal's shell, it isn't developing more armored forms for protection, as different animals of the same species have evolved.
Although science has not proven it, you can observe the behavior of a hermit crab when it sees a live snail and knows that its shell can be a potential home. This has been corroborated because examined groups of crabs following the mollusk, waiting for it to die.
Beyond this behavior, hermit crabs exhibit a particular ecological relationship with shells known as thanatocresiswhich consists of reusing the structures of dead organisms. For them, obtaining a good shell is a matter of survival, and when they are scarce, can fight among individuals for the best. Furthermore, they tend to prefer globular shells (wider) compared to the longer ones because they allow for better mobility and protection.
Description
It usually has a color reddish or brownThis depends on the environment where they live and the age of the crab. They typically vary in color from orange and bright red to grayish-brown, among others. They have 10 legs, the first two of which are claws. The right claw is larger than the left, and both have a rough, granular surface.
The next 4 pairs of legs It uses them for walking and the rest for gripping and staying inside the shell. It has two structures very similar to antennae that it uses to sense everything around it and observe its environment.
The front part of the crab is what we can see outside the shell. This part is covered by a rigid exoskeletonWhile its abdomen and entire rear end are much softer. This is why we can see the hermit crab curl its abdomen to retract into its shell. This is how it takes advantage of the protection. When it feels threatened, it uses its legs and claws to prevent the attacker from entering its shell and attacking its weakest point.
Furthermore, in many paguroids, the following stand out: ocular peduncles Thick and robust, they protrude from the face and enhance the perception of the environment. It is common for the left or right claw (depending on the species) to be more developedacting as a “gate” to block access to the shell. Some species have legs and claws covered in hairs or silks that increase sensitivity and the ability to manipulate food and substrate.
As for size, depending on the species they can be very small or reach several centimeters; many common coastal species measure up to 8 cm in length from the tip of the clamp to the end of the curved abdomen.
Hermit crab diet and habitat
This crab can eat almost anything. Many people call it a sea vacuum cleaner because it can eat nearly anything. Its diet is omnivorous and includes mussels, snails, worms, larvae and plantsetc. Furthermore, given its nature to utilize the shells of dead mollusks, it can also feed on dead animals. Just as with the blue crab It is able to get its own food by filtering all the organic particles that can serve as food.
Looking more closely at their diet, many species are primarily scavengersconsuming organic remains and keeping the seabed clean. However, they can also capture small invertebrates such as polychaete worms, small crustaceans, larvae, and even aquatic snails and juvenile bivalves. When resources are scarce, some species exhibit cannibalism opportunist. They also scrape and consume. seaweed fresh or decomposing food, and plant fragments found among sand and rocks.
Regarding its habitat and area of distribution, we find something too wide. And it is that it can be found all over the planet. Since it has an aquatic and somewhat more aquatic-coastal condition, it can live both in the deepest part of the sea and in the reefs, rocky areas of the coast and in the sand on the shore of some beaches. Usually, The deepest it has been seen is about 140 meters.
If they are on land, they prefer to live hidden in the rocks, but they must be very close to the coast to have the water. Regarding its distribution, it can be said that it prefers those areas with a tropical climate. It usually lives in greater abundance in the American and European continents. It's easy to spot one of these crabs if you go from Alaska to Mexico or from Guatemala to Chile.
Many coastal hermit crabs are intertidal (they live in the zone that alternates between immersion and emergence) and others are found in the first few meters of the infralittoralIn regions such as the Mediterranean Sea and Black Seaand in the eastern Atlantic, they typically prefer rocky bottoms with cracks and an abundance of empty shells of Nassarius, Monodonta, Calliostoma, Nucella, Gibula, Ocenebra, or Cerithium. Its shell, in addition to providing protection, retains waterThis allows them to keep their gills moist for short periods out of the water.
Taxonomy and classification
The hermit crab belongs to the Kingdom Animalia, Filo Arthropods, Subphylum crustacea, Class malacostraca, Order decapoda, Infraorder Anomur and Superfamily PaguroidThis superfamily includes families such as Paguridae, Diogenidae, Coenobitidae (which groups together several terrestrial species), Lithodidae, Parapaguridae, Pylochelidae and others. This classification explains why, although we call them "crabs", they are more closely related to lobsters and other anomurans that are with true crabs.
Defensive behavior and strategies
When a hermit crab grows up, it needs moltFirst, it meticulously inspects the interior and opening of available shells with its tweezers; if it finds a suitable one, it "moves" in a swift motion to minimize exposure time. During the brief interval between leaving the old shell and entering the new one, the animal remains helpless facing predators.
During periods of growth, many hermit crabs increase their body water content to approximately 70% of its weight This facilitates the breakdown of the old exoskeleton, a process after which their cuticle is soft and they are more vulnerable. During these phases, they seek safe havens and large shells that do not restrict their movement.
Some species establish a mutuality with stinging anemones which they attach to their shells. The anemones gain access to more food by moving, and the crab receives additional chemical protection; when they change shells, it is common for them to move “their” anemone gently. This behavior reduces predation. de peces and octopuses.
To regulate their exposure, many hermit crabs are nocturnalThey move mainly at night to feed. They are benthic, meaning they linked to the fund, and they rarely stray from it during their daily rounds.
Hermit crab reproduction
These animals have a oviparous reproductionThat is, they reproduce from eggs. Females typically reproduce twice a year. Their main breeding season is between January and February, when the hermit crab population lives along the seashore. It has been reported that females living in the depths can carry their eggs in their wombs for almost a year.
Once they have copulated, it is the females that carry the eggs under the abdomen for several months. Then he releases them into the sea and it is there that the larvae, with a pelagic lifestyle, remain adrift for a few weeks. Once they have hatched, they emerge in areas called zoes that are part of the plankton.
As they grow, they shed their skin very frequently. Only until you have 4 antennas and 2 clamps is when you will be able to find a shell that allows you to protect the rest of your body. Thanks to this protection they can now leave the beach and begin to develop the adult cap.
Expanding on this information, after hatching the larvae go through several stages of zoea and subsequently the phase of megalopawhich already exhibits pincers and behaviors more similar to the juvenile stage. Upon finding a suitable shell and settling on the bottom, they complete the metamorphosis into the adult stage JuvenileFertility can be high, with hundreds of offspring per clutch depending on the species, the size of the female and the availability of minerals such as calcium.
Relationship with humans, threats and conservation
As an key scavengers Within the ecosystem, hermit crabs contribute to nutrient recycling and keeping the seabed clean. However, they face threats such as... shell collection by people, which reduces the number of available refuges; pollution and loss of coastal habitats; and capture for the pet tradeTheir sale as pets has become popular in some places, but keeping them outside their natural habitat is often shorten your life and subject them to stress, especially if their environmental needs are not respected.
Responsible ownership of the land hermit crab
Some terrestrial species of the family Coenobitidae They are sold as pets. Although their upkeep is demanding and not recommended for beginners, if you decide to do so in an informed and legal manner, make sure you reproduce their environmental conditions and social:
- InstallationA terrarium or paludarium of at least 80 × 40 × 40 cm is suitable for a small group. The larger the enclosure, the better for their well-being.
- TemperatureIdeal temperature between 26 and 28 °C, avoiding exceeding 30 °C. At night it can drop to ~21 °C.
- HumidityHigh efficiency, between 70 and 90%. Sprays water without creating puddles and is monitored with a hygrometer.
- SubstratumAt least 10 cm deep with sand, fine gravel, humus, or pine bark. It must allow dig and retain moisture. You can add a lamp. infrared to keep warm.
- SecurityThey are skilled climbers; the terrarium must be leak proofIt provides elements for climbing (stones, roots, coconut mats) and hiding.
- WaterIt offers two shallow bowls, one with water sweet for hydration and moistening gills and another with saltwater (prepared with specific sea salt, never table salt) to provide minerals such as calcium.
- Vegetation and decorationNon-toxic plants adapted to high humidity, such as Ferns and mosses; shelters and logs to reduce stress.
- Minerals: add cuttlefish bone or sources of calcium to promote the formation of the exoskeleton after molting.
- ShellsIt offers several shells of different sizes and shapes (preferably round) always clean and without varnish. Continuous access to suitable "homes" reduces fighting and stress.
In captivity, their diet should be varied: protein sources (seafood, dried insects), vegetables, algae and dry leaves safe. Avoid processed foods and, when possible, encourage foraging Hiding small portions among the substrate. Remember that they are gregarious animals; keep them in a solitaria It can be counterproductive to your well-being.
While there are care measures that can improve their quality of life, the most responsible course of action is to find out about the legal origin of the specimens, prioritizing the adoption of individuals already rescued and to assess educational alternatives that do not involve their removal from the environment.
The hermit crab, with its surprising habit of molting to grow and survive, is an example of adaptation and the importance of available resources in nature. Understanding its biology, its ecological role as a nutrient recycler and the threats The challenges they face help us appreciate why we must protect their habitats and, if kept in captivity, always do so under highly responsible guidelines.
