#land crabs

[chunkfunkgunk-offishal]

coconut crab?

Today on CHUNK! FUNK! GUNK! We rate

the COCONUT CRAB:

5/10 Chunk

8/10 Funk

0-1/10 Gunk

Here you go, crab enjoyer. I know you’ve been asking for coconut crab for a while now lol

What a big guy! Though it is a crab and therefore majority carapace instead of skin or fat, it does have a big ol’ badonker so it can get a little chunk. While it is a pretty regular looking crab in my opinion, I do think that it is recognizable when compared to other crabs. Especially since I believe that it’s one of the largest (or THE largest) species of land crab. It gets to have a little higher than average funk. I could not find any information on its slime or mucous secretion, so I am left to assume that it is a dry little guy.

Overall: 5/10

A very solid and interesting crab. I feel like I would find them a lot more interesting if I could see one in real life, but from photos alone it does not have the ‘wow factor’ for me.

[aquariuminfobureau]

Although land crabs regularly appear in the exotic pet trade, there is not much care information around for these species, excepting the most widely traded of the land hermit crabs, Coenobita clypeatus. For a while much confusion surrounded the rainbow crab of West Africa, Cardisoma armatum, and the moon crabs of the grnus Gecarcinus, which are imported from the opposite side of the Atlantic. I had myself thought the moon crabs, traded at a smaller size than the rainbow crabs, were a growth stage of that species. The similarities were not merely superficial, because both genera are members of Gecarcinidae, a major clade of land dwelling crabs. At least two species of Gecarcinus were turning up, these being G. lateralis and G. quadratus.

A well studied species, G. lateralis might be thought of as the ordinary moon crab, and most of my scientific information pertains from descriptions of this species, which is also called the Bermuda land crab and the black-back land crab, as well as some other names. Whatever it is being called, G. lateralis is present in coastal environments, where it lives above the tide mark, including where there is no standing water. Reportedly G. lateralis can grow to attain a carapace as long as 10 to even 12 centimeters, or 4 to almost 5 inches, and a legspan that is 15 centimeters or 6 inches. If such specimens exist then they are rare. A study of the burrowing behavior of this species in forest habitat, did not indicate any of such large crabs, their carapaces measuring closer to 5 centimeters or 2 inches when mature. However in a related species, G. ruricola, large males and slightly smaller females are demonstrated to possess carapaces about 9 centimeters wide, whilst 5 or 6 centimeters would be a more common carapace width.

The related species G. quadratus also has many names, but the Halloween (moon or land) crab is by far the most widely encountered, at least in the exotic pet trade. It may also be encountered with the labelling of harlequin land crab, among others. These two names do not seem to be in use when referring to any other Gecarcinus species, all of which may for example be referred to as red land crabs or moon crabs - labels shared with land crabs from other gecarcinid genera. G. quadratus is a native of the coastal rainforests of Mexico and the Panamanian land bridge, that attaches North to South America. This species has a carapace length of about 5 centimeters or 2 inches. I do not have a clue as to how variable in size this species of Gecarcinus is. Although it is clear that mature members of species in Gecarcinus, may show size variation.

Although Gecarcinus sp. larvae are dependent upon saltwater for their survival, the adult crabs have no such requirement. Although they might be found on beaches and in estuarine environments, adult G. lateralis died at salinities of 30 and 35 ppt, whereas they flourished in freshwater, and at lower salinities of 15 and 20 ppt. I do not have information about the salinity tolerance of G. quadratus, but adults belonging to both species do perfectly fine with access only to fresh water. These crabs are obligate air breathers and no not, in fact, require an aquaterrarium, provided their substrate is damp, or they have access to shallow water in a bowl or dish. This is because these crabs take up water using their abdomens. G. lateralis is also known to ingest damp sand for its moisture content.

Both G. lateralis and G. quadratus are present in environments where the substrate allows for burrowing behavior, and there is plenty leaf litter. Conspecific crabs are present in vast numbers, might share an environment, and this might be thought apt for these species the aquaterrarium, considering their herding habits in the wild. Nonetheless, each of these crabs will need space to avoid the behavioral incidents arising from overstocking. Cohabiting crabs would also need a complex environment, which they can use to avoid confrontations among their kind when necessary, not least if they are molting, because the presence of conspecifics reduces the survival of molting crabs. These crabs molt inside their own burrows for protection during this vulnerable, temporary time. Although this genus has strong herbivorous leanings, the older crabs are known to kill their juvenile conspecifics for food, especially when they are under nutrient stress

Gecarcinus are classed among the herbivorous crabs, and they do possess the abilities to digest cellulose, and consume fibrous plant materials. However their herbivory is not total, and foods of animal origins are accepted. Their diets are 80% vegetarian whereas it is only 10% of arthropod origins, and they can consume both green and brown (dead) plant matter. Although they prefer to eat fresh plant material, the wild crabs might consume more leaf litter. G. lateralis is a significant consumer of seeds, fruits, and propagules, avoiding vegetable foods with strong alkaloid defences. There is reason to believe genus Gecarcinus consume a broader spectrum of foods in the dry season, including fruits and carrion. Cannibalism in these crabs increases when access to nitrogen is decreased.

Gecarcinus sp. are burrowing crabs, and they use their burrows to shelter in less hospitable seasons, plugging their burrow and storing leaves as their food supply, when the temperature drops and the air humidity decreases. This behavior assists them avoiding water loss in the dry season. For this reason the air temperatures in the vivarium housing Gecarcinus sp. should not drop as low as 15-18 degrees centigrade, unless one wishes to stimulate such behaviors, by simulating a Caribbean dry season. The crabs seem to use decreasing air temperature as their cue for this behavior, but are triggered to resume behavioral normalcy by increased rains and the return of higher air humidity.

These crabs in the vivarium require a dump substrate and a high air humidity of over 80%, based on the humidity inside crab burrows. The diurnal air temperature range, on a similar basis, should be closer to 28 degrees than to 20 degrees centigrade. People report success when keeping this species at 26 or 27 degrees by day. I have read that this temperature must not be allowed to fluctuate, but in the wild the air temperature in their habitats does drop a little by night, and Gecarcinus are night as well as day active foragers. If the environment makes them unhappy they will retreat into the microhabitats of their burrows. Although not necessary, these air breathing land crabs are easily accommodated in a paludarium, with a large land portion simulating a tropical forest floor.

The water portion of an aquaterrarium assists in maintaining a high air humidity, but these crabs do need to safely leave the water should they walk or fall in. For this reason any water area should be of a shallow depth, and the substrate ought to slope out of the water. As with all humid vivaria, it is also important that there is sufficient ventilation. Although the air should have a high moisture content, it does not follow that it be stagnant. I have not heard reports of Gecarcinus sp. being mixed with other species of land or water animals. However, gecarcinid crabs are strongly inclined to eat live plants, and destroy planted landscapes.

Gecarcinus are primarily feeders on edible fruits and vegetables, that will also accept proprietary defrosted and dry foods intended for aquarium fishes. Although they are predominantly vegetarians, Gecarcinus diets in the aquaterrarium should also include some animal proteins, to reflect their natural consumption of arthropod material, but they will also consume soybean based foods that offer a similar boost of nutrients. The opportunistic consumption of animal matter is a well known phenomenon in terrestrial crabs with herbivorous specializations.

[tenth-sentence]

Of native animals, land-crabs and rats swarm in numbers.

"Journal of Researches into the Natural History and Geology of the Countries Visited During the Voyage of H.M.S. Beagle Round the World, 1832-36" - Charles Darwin

[sealsdaily]

Today's Seal Is: Scouring for Crabs

[herpsandbirds]

Yellow Land Crab (Johngarthia lagostoma), family Gecarcinidae, Ascension Island in the South Atlantic

photograph by Drew Avery

[crabsnpersimmons]

It has come to my attention that I haven't drawn sun and moon as chibis yet

I have rectified the situation:

all is right with the world

[happycrabitat]

Thanksgiving dinner: hermit crab edition

[stargirl230]

Knight of Cups 🌷

My card illustration for the @novaandmali LGBTarot project! There are rainbows hidden in here if you squint :)

We're 99% funded with less than 4 days to go - help us get to 100% and unlock some cool stretch goals!

(no reposts; reblogs appreciated)

[daily-crabbys]

Today's crab is: buried halfway

[aquariuminfobureau]

For decades a colorful African crab, Cardisoma armatum, also known usually as the rainbow crab, has captivated and confused aquarists. This is the same species that is sometimes known as the Nigerian moon crab, lagoon land crab, and in the USA, the patriot crab. In the wild the rainbow crab is distributed from Senegal to Angola, and is present also in the Capo Verde islands that are offshore from Africa. Within this range the crab is noted to be present in lagoons and nearby estuaries, including mangrove habitats. Although rainbow crabs may be found around true freshwater environments, close to the riverbanks of freshwater stretches of rivers and in cultivated land, they are not distributed far from brackish water. This is because their larvae live in saltwater whereas their adults roam on land. C. armatum and other land and freshwater animals sharing this kind of life cycle, are thus constrained by their marine origins. Adult C. armatum are habitually nocturnal and they usually reside by day in their burrows, that they excavate into clay rich soils. Wild crabs of this species are observed to be more skittish than is normal for a terrestrial crab.

Field records demonstrate that wild rainbow crabs normally have a carapace a little below 9 centimeters or 3.5 inches length. Mature males of C. armatum are larger than their female counterparts, and their carapace length is slightly under half of its width across its broadest part. A rainbow crab with an 8.5 centimeter long carapace, is predicted to have a width of 18 centimeters, or around 7 inches. Reportedly very big C. armatum can grow until their carapace is as broad as 20 centimeters or 8 inches across, although this does not feel probable. A rainbow crab this size, which would assumedly be a mature male, would approach a 10 centimeter or 4 inch carapace length. Similarly other sources indicate that big male rainbow crabs have a carapace 12 centimeters long, which is above 5 inches. A crab this size would be 25 centimeters or nearly 10 inches across their carapace.

The dietary ecology of C. armatum is fortunately well studied, and this species is regarded to be omnivorous though with herbivorous specializations. Macrophyte material in fact constitutes the primary diet of C. armatum, being about twice as important in its diet as insect material. Although their consumption of insectile material is significant, they do not eat very much of mollusc, annelid, vertebrate, or aquatic arthropod material. Items in all of these categories were found to be consumed by these crabs, though they only make up a small proportion of their total diet. Cardisoma sp. shun brown leaf litter as food, for that which is fresh and green, a preference leading to niche partitioning alongside other crabs such as Gecarcinus sp. In the wild the diet of C. armatum includes the fallen fruits of trees, including the oil rich fruits of oil and coconut palms.

In Cameroon, it is noted that C. armatum is one of the less amphibious of the crab species found associated with estuaries. Crabs of this species may in fact be found 70 meters away from the nearest waterside, justifying their status as terrestrial crabs. They are obligate air breathers, and they hold their breaths when they have to submerge themselves Significantly the rainbow crab is found only in the low salinity zone of the estuary, and even in adjacent freshwater stretches. There the average annual air temperature is close to 27 degrees, and the humidity of the hair is very high, even approaching a value of 100%.

Because these are terrestrial crabs, water parameters are not highly important as long as it is safe to drink, except during the period of their life cycle before their metamorphosis into land crabs, during which time they are a portion of the saltwater plankton. Collection records demonstrate the adult C. armatum to be adverse to high salinities, being present from freshwater or 0 ppt salinity, up to 7ppt salinity, which is a mere 1.005 as specific gravity. It seems to be the reliance of C. armatum on the sea for only its early life stages, that limits this species to coastal habitats. The water temperature where they are present has been recorded to be 27-29 degrees centigrade, and its pH has a circumneutral value between 6 and 8. Recorded air temperatures at these localities may match those of the water, or be slightly higher by one degree or so.

In the aquaterrarium, C. armatum are quite capable of overpowering fish, smaller crabs, and other motile animals for the purpose of eating them, although they are of course foragers rather than active predators. Molluscs might not be important dietary items for C. armatum, but they are nonetheless recorded as natural dietary elements. Cannibalism is known in this species, which also has a reputation for being aggressive and territorial in captivity. There is reason to think this is based on their poor conditions during shipping, and improper housing sfterwards. Nonetheless, C. armatum are not an exceptionally common terrestrial crab in the wild, and they do not form vast herds like some other land crabs, despite their vegetarian leanings. They have lower population densities than herd forming species of mangrove associated crabs, and they really are territorial. If cohabiting two or more individuals is to be attempted, there is an element of risk. The land portion in the shared environment must be appropriately large, and it's landscaping topographically complex. Competition for food, water, and burrows must be low. Living plants will likely be eaten by these unfussy omnivores, but decor can include dead leaves, and the substrate should be sufficiently deep and firm for burrow excavation..

On a more positive note for the crab fancier, rainbow crabs readily adapt to a broad range of foods, from sinking pellets to fresh fruits and vegetables. This species has also been maintained on a staple diet derived from cereals and arthropods. My own C. armatum showed little interest in shellfish from the fishmongers, but they would consume freeze dried arthropods and worms when they were moistened. Although animal food sources are an important dietary element, preventing nutrient deficiencies in the wild crabs, the vegetable component of their diet is more important to them. They will eat proprietary algae wafers, but also fruits and vegetables safe for human consumption. Certainly they eat the oily fruits of palms, including broken coconuts, and this is an ideal dietary component that they utilize in the wild. They will also devour other fruits such as pieces of bananas, and some green leaf vegetables.

[thewallsaretalking-again]

*Throws comic into the eather*

[dazzelmethat]

Sea water spider. It is a water spider that mimics a jellyfish. Females can stick their silk to an object on the surface to pull themselves up later to nest closer to the shore. Males just drift like a jellyfish.

Speculative biology for if there were salt water bugs.

[herpsandbirds]

Yellow Land Crab (Johngarthia lagostoma), family Gecarcinidae, Trindade Island in the South Atlantic

photograph by Fernando Faciole

[patrickelvinart]

black sharpie on paper

Miami 2009

I lived in Miami for a few years. I rented a small apartment right on the bay. It was lovely. Land crabs and iguanas used to wander around the yard. Beat that!

Miami has some of the most beautiful beaches on earth. White sands and tropical blue water. I used to hang out at beach cafes and draw.

Back then my main drawing tool was the black ultrafine sharpie. I was into drawing quilts. Crisp black and while images drawn off the cuff.

Here's another one.

Hermanos Gutierrez - Hijos del sol

black sharpie on manila paper

Miami 2010

Bay Harbor beach, Miami, 2009

.

[happycrabitat]

A busy night in the hermit crab tank!

[itissadbutitsmy-artblog]

im the most normal person at the party

^ my reference picture to prove im not crazy. or to prove im extra crazy.