Red Crab Geographic Range: The Biggest Crustacean March You Can Witness | Kidadl


Red Crab Geographic Range: The Biggest Crustacean March You Can Witness

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The Christmas Island red crab species is a pervasive land crab found only on Christmas Island as well as the Cocos Archipelagos in the Indian Ocean.

Even though this crab is limited to a small region, approximately 43.7 million individual red crabs lived on Christmas Island on their own once upon a time. However, the inadvertent emergence of the yellow crazy ant is thought to have victimized 10–15 million of these crabs in past years.

Christmas Island is a part of the continent of Australia. Most of these red crabs belong to Christmas Island, but some are also found on the Aleutian Islands. The Aleutian Islands are a part of the United States and some part of these islands belong to Russia. Red crabs from Christmas Island embark on an annual migration which is a massive immigration to the sea to leave their eggs at the bottom of the sea. Despite the fact that its population is being decimated by ants, the International Union for Conservation of Nature still hasn't evaluated the red crab and it was not on their Red List as of 2020. The carapace of Christmas Island red crabs can measure up to 4.5 in (116 mm).

Their claws are generally comparable in length, unless one is injured or completely disconnected, in which particular instance the limb regenerates. Male crabs are typically larger than females, whereas adult females have a much wider abdomen and relatively small claws. Their most common color is bright red, which is how they got their name red crab, but as well as bright red, they can also be an incredibly rare burgundy.

Adult females are very cautious and analyze phases of the moon in order to wait for the high tide and only then release their eggs in the water. Christmas Island red crabs were once considered a delicacy in British Columbia. After reading about the red crab habitat range, also check out interesting facts about the red crab habitat and the red crab lifespan.

How big do red crabs grow?

Red king crabs are large crabs. Adult females have shells, which are also known as carapace, which can be up to 4.5 in (116 mm) in length if it is measured horizontally and not vertically. The carapace of the Christmas Island red crab is round-shouldered and includes the lung tissue and gills. If one of their claws is growing back, their claws are generally of equivalent length.

Red king crabs are found in Australia and they often come to the shore to mate and breed. Male crabs usually arrive earlier and wait for females. They dig their holes on the shoreline and have to defend their nest from other male crabs. Smaller crabs usually get defeated by bigger ones and their nest is overtaken by the bigger crab before mating.

Mating takes place inside these same holes when females emerge from the forest to find a suitable male crab at the shore. After the mating is complete the male crab returns to the forest while the female remains in the hole for a few days to incubate the fertilized eggs. The crab then releases these eggs into the ocean or sea where eggs and larvae float in open waters and are left to survive by themselves. They rarely ever reach the ocean bottom and just float around until they mature. This crab species found in Australia is very rare.

Red crabs, like most land crabs, breathe through their gills and must take great care to keep their bodies moist. The mass red crab migration on Christmas Island is one of the most incredible natural processes on the planet. The red crab’s migration is what baffles the world so much. Red crabs are fairly large crabs and millions of them rush to the sea coast every year at the same time to mate and lay their eggs as a part of their annual migration. Female crabs release their eggs into the sea during the high tide after they are incubated and then return to the rain forest where they live.

What do red crabs feed on?

Red crabs live in deep cracks in rocks or they dig tunnels. They are a water-sensitive sea species and generally avoid leaving their holes in the ground during summer months. They plug the opening with a pile of foliage in order to ensure better protection.

They primarily consume dead leaves, fruit and vegetables, flower petals, and seeds. They are not completely vegetarian, even so, and will consume other dying crustaceans, wildlife, and, if present, they will also devour a giant African snail. Red crabs help to maintain the wellbeing of the tropical forest by preferentially consuming vegetation, cleaning up fallen leaves, turning over the land, as well as fertilizing it with their excrement.

Every year, the red crab relocation to Christmas Island happens at the start of the rainy season. This also happens to be the only time they leave their burrows for something other than food which is to lay their eggs in the sea. They feed on any matter which can be consumed. They rarely ever leave their hiding spots so they don't require a lot of energy to run their body. The crab gets nutrients by eating fallen leaves, dead and decaying matter and flowers. It doesn't sound like a lot but it is enough for the red crab to sustain its life.

The only time the red crab requires a lot of energy is when it migrates to Christmas island. Millions of crabs lose their lives during this journey as they may get crushed under vehicles or die from lack of nutrition and moisture.

Christmas Island red crab is pervasive land crab

Are red crabs edible?

Red crabs are not the type of crabs you'd find at a fish market. Their meat is 96 percent water, and they are simply too small and lack flavor to be regarded as appetizing. The flesh is very pale with a distinguishable red pigmentation on the outside, similar to the flesh of the lobster.

They're not safe to eat. Crabs seem to be poisonous rather than venomous. Furthermore, they really aren't genuinely poisonous, which means they do not produce their own toxic substance. Highly toxic ones can transport a fatal dose of toxic elements inside of their inner organs, but they do not generate contaminants.

Red crabs are not tasty to eat like other seafood. They have way too much water and very little flesh. They are also not very big like other crustaceans which makes them very difficult to eat. To eat a crab you normally have to take a long and thin knife and clean out the flesh from inside the hard outer shell of the crab. A lot of time and patience goes into doing so. The flesh on the body of a red crab is so minimal that it is hardly worth the time it takes to prepare the crab and take out the flesh.

Why do red crabs migrate in such huge numbers?

The migration begins with the very first rains of the rainy season. This typically occurs in October and November, but it can occur close to the end of January. Red crabs leave their homes at the same time and begin trudging toward the sea to copulate and lay eggs.

Male crabs guide the flow of migrants, and females participate with them along in the same direction. The phase of the moon determines the exact duration and maneuverability of the population movement. Red crabs invariably reproduce before sunrise during the last quarter of the lunar surface on a retreating high tide. They know precisely when and how to depart from their underground tunnels to meet the lunar deadline.

Red crabs, on the other hand, must sometimes hurry because they wait until the first rain to begin their journey. The rains will move quickly if they arrive close to the optimal spawning date. However, if the monsoon arrives slightly earlier, they may bide their chances, halting to drink and eat along the direction of their destination. If it starts raining excessively late to make the hatching timeline, a few red crabs will remain in their tunnels and move later that month.

During the mating season, male crabs move to the sea before female crabs but eventually, female crabs outnumber male crabs.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for 'red crab geographic range: the biggest crustacean march you can witness' then why not take a look at how many legs does a crab have or spider crab size.

Kidadl Team
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Kidadl Team

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