Land Crabs :
Land Crabs ..... Part One : Hermit Crabs
Land Crabs ..... Part Two : Other Land Crabs .. Halooen Crabs
Land Crabs ..... Part Three : The Giant Coconut Crab and others least concern
A number of lineages of crabs have evolved to live predominantly on land. Examples of terrestrial crabs are found in the families Gecarcinidae and Gecarcinucidae, as well as in selected genera from other families, such as Sesarma, although the term "land crab" is often used to mean solely the family Gecarcinidae.
Terrestriality and migration:
There is no clear distinction between "terrestrial", "semi-terrestrial", and "aquatic" crabs. Rather, there is a continuum of terrestriality displayed among the true crabs, although even the most land-adapted crabs must still return to water to release their eggs. Some species of terrestrial crabs can be found many kilometres from the
For more information also read :
sea, but have to complete annual migrations to the sea. For example, following the Indian Ocean monsoon, the Christmas Island red crab (Gecarcoidea natalis) migrates en masse, forming a "living carpet" of crabs. The crabs can travel up to 1.46 km (0.91 mi) in a day, and up to 4 km (2.5 mi) in total.!
Terrestrial crabs have often evolved from freshwater crabs, since the physiological changes needed for living in fresh water are pre-adaptations for terrestrial living. On some oceanic islands, terrestrial crabs occupy the top of the energy pyramid.
Swarming Cuban Land Crabs
March of the Red Crabs - Lands of the Monsoon - BBC
Giant Blue Land Crabs
Crabs Species and care :
Land hermit crab
AN INTRODUCTION TO HERMIT CRABS
Land hermit crabs are crustaceans known as Coenobita clypeatus. They live in the wild in the western Alantic. Hermit crabs have a three sections: a head, a body (cephalothorax), and an abdomen which they protect with their shells. Hermit crabs have gills on their big claw in order to conserve moisture. Hermit crabs sometimes go for long periods of time without food or water. However, hermit crabs need to keep their gills wet to maintain good health. It is usually best to place them in or near water once a day. Although hermit crabs might look harmless, they can use their claws to grip things tightly. Trust me; I've had one attached to me for five minutes. If one should attach themselves to you, put them under luke warm water. Even the very smallest hermit crabs can draw blood if it becomes frightened. Hermit crabs usually travel in groups of 25 (approx.) in the wild. So it is important when you have hermit crabs as pets that you have several of them to keep each other company.
Hermit Crab Growth :
Hermit crabs do not reproduce in captivity. Instead, they mate on land near the sea. After the eggs develop, the female carries the eggs on her abdomen to the sea where she leaves them on wet sand or a wet rock for the tide to carry them out to sea. There are usually 1,000 to 50,000 eggs at a time. They are small larvae at sea where they molt several times in order to grow to reach the characteristics of a typical adult hermit crab. After reaching the adult larvae stage, the hermit crabs begin looking for a shell to live in. Once they mature and find a suitable shell, they come to live on land for the rest of their lives. Hermit crabs grow on land by shedding their exoskeleton. At first glance, you might think your hermit crab has died. But, you might want to make sure by looking inside the shell to see if your crab has died or just molted. It takes about ten days for a hermit crab's skin to harden after molting. During this time, it is best that they are in a warm environment. Shedding is a necessary part of their livelihood since they will grow back missing legs during this time. In the wild, hermit crabs can live up to 25-30 years. But normally in capitivity they live around 1 year. Although, my first hermit crab, Fred, lived to be over 4 years old. The search for a new shell continues throughout a crab's life since it is either searching for a more comfortable shell or a larger one as it grows. Once a suitable shell is found, a crab will inspect it in every possible way. It checks the shape and opening thoroughly with antennaes and legs. The crab may insert a claw to explore the interior to roll the shell on all sides. This way hermit crabs decide whether or not the shell is a suitable home. If the crab decides to try the new shell on for a trial fit, the crab will insert its abdomen into the new shell while still holding onto the old one. Shell changes are done quickly since the hermit crabs are vulnerable to predators without their shells. However, I've had a crab walk around on my floor for 3 days without his shell on. I guess he felt that he was in no threat of danger. If this does happen, try to seperate the crab from from your other crabs since it is in a vulnerable state. The only time you will be able to determine whether your hermit crab is male or female is when it is out of its shell.
What Hermit Crabs Eat :
Hermit crabs can eat a variety of foods. In the wild they are scavangers and will eat about anything. However, they do have a strong sense of smell which is an important thing to remember when you are selecting food for your hermit crabs. Usually, a good diet for a hermit crab is any hermit crab food in pet stores. Hermit crabs like a variety of fruits (apples, coconut, grapes). Also, hermit crabs need salty foods in their diet. Salted pretzels or bacon bits can give them the salt they need. Another important part of a hermit crab's diet is fresh drinking water. The water dish should be a non-metal container. The two most common water dishes for hermit crab's are plastic lids or shells. When crabs drink out of a shell, they receive calcium from the shell that they need in their daily diet. The main thing to remember when selecting a water dish for your hermit crabs is that it is not too deep. Hermit crabs can drown if they crawl into a deep water dish and can't climb out. Place your hermit crab near the water dish daily so they can moisten their gills which they breathe through.
Hermit Crab Environments:
The most common environment for hermit crabs as pets are 10 gallon aquariums. The aquarium should have 2-3 inches of gravel. It is always better to wash the stones off with water before placing them into the tank. You should have some coral rock in the aquarium for your hermit crabs to crawl around on. Also, extra shells can be left in the tank for decoration or on the rare occasion that your hermit crab might decide to change shells. Hermit crabs need to live in temperatures between 70-85 degrees. If the air is too cold or dry, the crabs will become inactive. Hermit crabs do not like to walk around a wet sloppy cage, but prefer to be in a dry aquarium with lots of moisture in the air. If you put your hermit crabs outside of the aquarium and you can't find them, don't worry. They can store water, so they can go for long periods of time without water. Hermit crabs can go up to one year without any food or water. Also in the wild, some hermit crabs live in trees. So, it is a good ideal that you have a place for your hermit crabs to climb. Usually, a laundry basket with small holes will work. But, make sure you put something to hold down the lid because most hermit crabs can lift the lid and climb out.
Hermit Crab Behavior
Hermit crabs are nocturnal, so they may seem inactive during the day. But if you wake your hermit crabs up during the day, they usually sleep during the night. It is important for a hermit crab's well being that they get excercise outside the the cage. I found that since I started to let them out of their cages to roam free, they seem to live longer on the average. Usually, hermit crabs will go towards dark areas, such as under a couch, since they are nocturnal. If you do let them out of the aquarium, it is important that you watch where they go. It can be amusing to watch them run across the room. Unlike most people, I let my crabs out a day or two at a time. They like to wander in and out of my C.D. case. Also, I have two crabs too large to fit comfortably into my ten gallon, so I just let them run free in my room. Although, I have had to take some precautions in doing so- making sure they can't get behind furniture and that all electric cords are off the ground. I found that they keep out of the walkways, but you should still watch each step you take. They seem to like having the freedom to move, but they always return to the same location eventually. I feel that giving crabs the freedom to wander around is a more natural lifestyle for a crab to live in. Since I started to let my crabs spend most of their time outside the cage, they live longer. They live between 1-4 years on the average; where as before, I was lucky if they lived for 6 months in the aquarium. And I have noticed that large hermit crabs are not aggressive towards smaller hermit crabs. Usually, hermit crabs are only aggressive to hermit crabs of similiar sizes.
LAND HERMIT CRABLAND HERMIT CRAB
Think Tank's hermit crab exhibit and the associated panel "Shell Seekers" provide visitors with an opportunity to explore the definition of tools and the evidence of thinking during tool use.
DISTRIBUTION AND HABITAT
Land hermit crabs of many different species are found in tropical areas of the Indo-region, the western Atlantic, and the western Caribbean. They live close to the shoreline and must have access to land and water. There are also entirely aquatic species of hermit crabs.
The front half of a hermit crab is covered with a hard exoskeleton (hard outer skin). The long abdomen has a softer exoskeleton, that can adjust to fit into a spiraled snail shell. A crab presses its abdomen against the shell's inner wall by contracting its longitudinal muscles. The large left claw is used for defense, for holding onto tree limbs, and for balance. The smaller right claw and the next pair of appendages are used for collecting and passing food and water to the mouth. Hermit crabs have stalked eyes with acute vision and two pairs of antennae. The longer pair of antennae is used for feeling, the shorter for smelling and tasting.
As a hermit crab grows, it molts, shedding its exoskeleton and creating a new, larger one. A crab builds up enough water pressure in its body to split the old skin. A crab may eat its molted skin, possibly for its calcium, vitamins, and minerals.
Hermit crabs use shells for protection from predators and dehydration. A hermit crab has a ranked hierarchy of fixed motor patterns that it goes through when choosing a new shell. Image and intention may be part of the pattern, but that does not mean thinking is occurring. The steps are always the same, in the same order, and show no flexibility.
In the wild, hermit crabs are omnivorous scavengers, meaning they eat whatever they can find. At the Zoo, they are fed fish food, crab food, and various fruits and vegetables.
Land hermit crabs live about ten years.
Hermit crabs mate in saltwater. Both males and females partially emerge from their shells to mate. After the eggs hatch, the larvae go through several aquatic life stages and molts. When they reach adulthood, the crabs migrate to begin their terrestrial life.
Land hermit crabs are good climbers and should be kept in a covered container. They need a good supply of empty shells to try on after molting. Hermit crabs also need high humidity and should be able to go into water. At the Zoo, petroleum jelly is used around the edges of the tank to keep ants out. Hermit crabs are not aggressive, but the large, purple claw can give a nasty pinch — so zookeepers handle them with care!
CARING FOR HERMIT CRABS:
The National Zoo does not encourage purchasing any type of exotic pets. However, if you do own hermit crabs, we encourage you to read through the following information to best care.
Providing hermit crabs with the right type of housing and food can help them live for several years.
Here are several guidelines to keep a hermit crab happy and healthy.
-Housing: Glass aquariums (10 gallon size minimum) with mesh and glass lids are the very best homes for hermit crabs. Plastic containers commonly marketed for hermit crabs are not good because they cannot hold in heat or humidity like glass can. Aquariums and mesh lids are available in most pet stores, and you can have glass cut to fit the top at most home improvement or hardware stores.
Building a great Crabitat ( Hermit Crab Habitat ) :
Below is courtesy to : www.pet-crabs.com/articles/building-great-crabitat/3
First and foremost, the goal is to mimic a native tropical climate so temperature and humidity regulation are key to a land hermit crabs survival.
Temperature Guidelines: 70-80 degrees F (78 degrees F is ideal)
Humidity Guidelines: 70-80%
Is it a bit stuffy in here? Having a saturated sea sponge in their home can help keep the proper humidity level. Buy a thermometer and hygrometer (measures humidity) so that you can monitor these two crucial environmental conditions daily. Land hermit crabs breathe with modified gills and if temperature and/or humidity fluctuate too severely, it can be fatal.
Location, location, location! Choose a spot for your crabitat where you will see your crabs often, making it easier to remember to feed, water and look after them. Keep in mind that they are nocturnal, and will be livelier at night so a bedroom is usually the worst place to house them.
Would you like your hermit crab in glass or plastic??? Most people house their land hermit crabs in an aquarium or create a terrarium for them to live in. A crabitat does not have to cost a lot, though. I’ve seen many people and pet stores house their crabs in plastic tubs or containers. The most important thing is that they have enough space for the essentials: two water dishes (one filled with dechlorinated water and the other with sea water), one food dish, a few things to climb on, an area to live in, and it should be tall enough to have a healthy depth of sand for burying themselves.
They certainly aren't pole vaulters but..... Once you choose a home for your land hermit crab, make sure it has a lid. Hermit crabs are very clever and can get out of their cages very easily. Lids can help prevent escapes and maintain humidity.
Smelly things are more than just stinky to a crab. Be cautious about exposure to fumes from soaps, perfume or cologne, hairsprays, household cleaners, and pesticides. They all can be harmful to your hermit crabs, so pick a spot for their home that will not be in direct contact with any of these things.
Below some photos for examples of successful setups :
Hermit Crab Habitats, How to Create :
courtesy to : m.drsfostersmith.com/pic/article.cfm?aid=2386
Setting up a hermit crab habitat, or "crabitat," correctly is very important for the overall health of your hermit crabs. Many potential hermit crab owners think that the small plastic cages they see in pet stores are what hermit crabs require, but that couldn't be further from the truth! Hermit crabs are not the easy, throw away pets that many people believe them to be, and setting up a proper habitat takes time and effort. The following information will teach you about what hermit crabs need in a safe, healthy environment and give you an idea of whether or not you would be able to keep hermit crabs as pets.
A . Fresh Air Screen Cover
B . Dome Light with Ceramic Heater or Incandescent Bulb
C . Fluorescent Strip Light with Full Spectrum Bulb, on a Timer
D . Eco Earth, Sand, or Crushed Coral substrate
E . Thermometers and Hygrometer
F . Dishes, for Food, Freshwater and Saltwater
G . Under Tank Heater (UTH)
H . Hiding and climbing accessories, like Plants, rocks, Driftwood, or cholla branches
I . Air Pump, Airline Tubing, and Airstone for bubble dish
Never use a small plastic container to house your hermit crabs. They need plenty of room to climb and move around. The smallest enclosure you should use for two small to medium sized hermit crabs is a 10 gallon aquarium. Housing multiple medium sized hermit crabs or two large hermit crabs can require an aquarium as large as 30 or 40 gallons.
Hermit crabs are good escape artists, so the enclosure will need a secure lid. If your house is humid and warm, you can use a wire mesh lid with latches. However, if there is a chance that the dry air in your home will affect the humidity levels of the habitat, we recommend the use of a glass or Plexiglas lid. You could also use a wire mesh lid with most of the lid covered by plastic wrap.
Though it is important to keep the enclosure warm, never place it on a windowsill or anywhere else that it will be in direct sunlight. This will raise the temperature dangerously high, and you run the risk of actually baking your hermit crabs.
You should choose a substrate that is easy to clean and that will allow your hermit crabs to tunnel and burrow in it. The two preferred substrates are sand and coconut fiber substrate. You can purchase special terrarium sand or play sand. Coconut fiber substrate such as Eco Earth works well also, and is especially good for tunneling and burrowing. Many hermit crab owners elect to use a combination of the two. Crushed coral is also an option for substrate. Avoid gravel, wood chips, or other substrates that are unsafe or do not allow them to dig.
Decorations and Accessories
Hermit crabs love to climb, so they will need plenty of accessories in their cage for entertainment. The following items work well as decorations in a hermit crab enclosure:
Fake plants and vines
Driftwood and branches
Wooden or plastic shelters
In addition to the above accessories, you will also need to place two water dishes in the habitat - one for fresh water and one for saltwater. They should be big enough that your hermit crabs can submerge themselves, but set up in such a way that it is easy for your crab to get in and out of them. The fresh water container should hold spring water or de-chlorinated water. The saltwater container should be a mixture of de-chlorinated or spring water and a special aquarium salt mix (regular table salt is not acceptable). We recommend putting these dishes in a low area of the habitat to mimic a shoreline, as hermit crabs would generally live near the ocean.
You should also place extra shells around the habitat for the hermit crabs to change into. There should be at least three shells per hermit crab, and the shells should be at least as big as or slightly larger than the crab's current shell.
Humidity levels are very important to the survival of hermit crabs. Hermit crabs have modified gills that allow them to breathe, but to be able to breathe, they need to breathe moistened air. Air that is too dry will actually dry out their gills, making it increasingly difficult to breathe until they finally end up suffocating. This is why their habitat needs to have a moist, tropical feel and a relative humidity that is no lower than 70%.
To help keep humidity levels where they need to be, keep the substrate damp, and avoid using substrates that do not retain moisture well. However, the substrate should not be soaking wet, as humidity that is too high can cause health issues as well. We recommend moistening the low and middle areas of substrate while leaving the higher hills dry. You can also mist the entire enclosure daily to provide plenty of moisture in the air.
Another way to maintain humidity levels is to use bubble bowls made from airstones, airline tubing, and air pumps typically used for aquariums. Simply put an airstone in the bowl of water and use the tubing to connect the airstone to the pump. This will cause the water in the bowl to bubble and circulate, increasing humidity as well as helping to keep the water fresh.
Always have a hygrometer in the habitat to monitor humidity levels. Guessing or approximating humidity levels can result in the death of your hermit crab. Be sure to check whether your hygrometer measures relative or actual humidity. Relative humidity levels should be 75% to 90%. Actual humidity levels will be approximately 50% to 60%.
Keeping within your hermit crab's temperature range is equally as important. Temperatures that are too high will cause irreversible heat damage, and improperly low temperatures will alter a hermit crab's metabolism. You may need to use outside heat sources to maintain temperatures within the habitat, especially during colder winter months. Primary heat sources can includeunder tank heaters and 15 watt reptile heat lamps. The temperature of the habitat should always be monitored with a thermometer.
Many people do not use special lights for their hermit crab's habitat, but lights can be very beneficial, both for providing healthy daylight and for maintaining proper temperature. When choosing lights, pay close attention to wattage. Lights with a high wattage over a small tank will cause the humidity to drop below proper levels as well as raise the temperatures into a dangerous range for your crabs. We recommend the use of a 15 watt bulb for a 10 gallon tank. The bigger the tank, the higher the wattage can be, such as a 60 watt bulb for a 55 gallon tank.
Lights that you can use include fluorescent bulbs that provide UVB and UVA light, incandescent bulbs, nighttime heating lamps, or a combination of these. You should use a timer to make sure that the light cycles are maintained appropriately.
Regular cleaning is necessary to keep your hermit crabs healthy and their environment safe. The following tasks should be part of your cleaning routine:
Spot clean substrate by straining the sand to remove waste and debris.
Change food and water as needed (when soiled, or when film starts to build up on the bottom of the dish).
Wash food and water dishes as needed.
We also recommend that you change the substrate completely at least once a month or more often if you see flies, gnats, or any other insects inside the enclosure. At this time, you can remove all of the accessories, wash the enclosure with vinegar and water (rinsing thoroughly), and boil toys and empty shells.
A Note about Safety
Always set up the enclosure before bringing home your hermit crabs. It is crucial that you stabilize the temperature and humidity levels before putting any crabs in the habitat. The hermit crabs you bring home will already be under stress, and putting them into an enclosure with improper or fluctuating temperatures and humidity levels can cause serious adverse side effects including lethargy, loss of limbs, and even death.
Setting Up the Habitat
Now that you know what should go into the habitat, it's time to learn exactly how to set it up! The following list will give you a step by step guide to setting up your crabitat.
1-Clean the aquarium with a biodegradable cleaner and rinse thoroughly.
2-After it has fully dried, attach the under tank heater, if you are using one, and add the substrate.
3-Add the decorations, water bowls, and food dish.
4-Attach the thermometer and hygrometer to the side of the habitat so you can monitor temperature and humidity, and put the lid on.
As you can see, properly caring for hermit crabs takes time and effort. Though they are often purchased as pets for children, we recommend that they remain a family pet with the responsibility of day to day care and habitat maintenance falling on a parent.
Some Videos :
Recommended Websites :
- Coenobita species : www.coenobitaspecies.com/
Further Reading :
Hermit Crabs- Care and Keeping! All you need to know!
Amazing Crabs Shell Exchange - Life Story - BBC
Hermit Crab Handling
All Basic Hermit Crab Care in Ten Minutes!
April 3, 2014
by Charles Sure (Author)
February 1, 2015
by Jeni Wittrock (Author), Gail Saunders-Smith (Consultant Editor)
April 23, 2007
by Kelli A. Wilkins
March 1, 2010
by Sue Fo
March 1, 2011
by Carol Frischmann
December 12, 2013
by Mr Mystery Adams (Author)
Land Crabs ..... Part One : Hermit Crabs
Land Crabs ..... Part Two : Other Land Crabs .. Halooen Crabs
Land Crabs ..... Part Three : The Giant Coconut Crab and others least concern