Red Crabs: Characteristics, reproduction care and more

It’s time to learn about the american red crabs or Procambarus clarkii in scientific terms. These creatures are decapod crustaceans that belong to the family of crayfish.

Red Crabs Main Characteristics

These animals are native to the United States, but can also be seen in other continents, where they are mostly known as an invasive species. We can mention the case of Spain, where they are known as American crabs.

The red crabs inhabit not very cold water, which means that they live in rivers, preferably of calm waters. They are considered one of the species with the greatest adaptation to ecosystems, and can grow rapidly in seasonal waters

In this sense we can mention that they withstand the dry seasons of the year, for four months and even more. They reach up to 50 grams of weight and can measure up to 12 centimeters.

However, it is good to know that they are able also to tolerate saline waters, but they do not usually stay there for a long time.

Red crabs live approximately 5 years or even 6 in some cases and they feed on vegetables or animals.

Red Crabs Anatomical Features

The red crabs have many peculiarities in their bodies and it is a good idea to know them. Each living being has particular characteristics, although sometimes those belonging to the same family may seem identical.

Let’s start by mentioning their teeth  which are located in their stomach representing this way a distinctive feature of them.

In terms of size, it can be mentioned that they are very small, reaching a maximum of twelve centimeters in length. A specimen of twenty three centimeters was found on one occasion, but this measure is not very common in them.

As they are decapods, they have five pairs of legs inserted in their belly. The first pair correspond to two well-developed pincers, which they use to capture and manipulate their food. The following legs are also pincers, but much smaller than the previous ones; and the last two strangely possess nails.

Excluding the first pair of legs, where the red crabs have the largest pincers, the rest are used for displacement purposes.

If for any reason they lose one of their pincers, it regenerates and is reborn, which is a common feature in most species of crabs.

American red crabs also have an external skeleton known as an exoskeleton which they molt several times in their lives.

To differentiate a male red crab from the female, it is recommended to observe their abdomens since the male has a much narrower one and the female has a much wider one.

These crabs are very appreciated in different countries and there are many of them, which prohibit their hunting, since they are usually in danger of extinction.


Unlike the common crabs, the red crabs have an elongated body, which makes them different from other crabs, but at the same time, makes them very similar to lobsters. See our article crayfish for more information about the anatomical characteristics of these crabs.

Other Aspects

Red crabs, like most river species, flee from sunlight. They are active only from night to dawn. Therefore, they tend to hide in holes dug in the sand and under the stones.These crustaceans are also characterized for being few friendly, since they are capable of fighting against their own species to maintain their territory.

The red crabs can live peacefully on  the land, but they have to constantly wet their pincers, which is why, most of the time, they are usually seen on the shore.

Way to Communicate with their equals?

Red crabs are usually good communicators, even one of the best in the animal Kingdome, since they usually move their pincers a lot when they do. So , whenever you see a crab moving, you know that it is communicating with those of its same species.

Another good characteristic of the red crabs, is that they usually work as a team, especially when they are looking for food. They usually support each other and at the moment of taking care of their families, they also do it among many of them.

They are great swimmers and they do it from side to side. It may seem like a jocular behavior, but it’s real. So, don´t laugh when you see a red crab swimming sideways, since it’s nothing supernatural, and is one of the many characteristics, which makes them differentiate from many other animal species.

Alimentation Habits

These crabs usually feed on invertebrate animals, fish, and vegetables. Moreover, crabs of their same species can also comprise their diet, as long as they are totally dead.

Let´s keep learning about this wonderful species.


 Red Crabs Reproduction

Let’s talk now about the reproduction process of the American red crabs. For this process it is necessary that the male is larger than the female, because to achieve copulation, he has to hold the female and place her belly down.

This mating occurs just after the female has molted her exoskeleton, since that structure is softer at that time, which facilitates the process. To be able to gestate, the males place their sperm inside the females, and this fluid remains within them for many days, until the arrival their fertile days.

Female red crabs can hold up to 700 eggs, depending on their size, which they carry during a period of 30 days until the eggs hatch. (See our article crayfish, for more information about this process.)

Watch this video to keep learning

Red Crabs Distribution

This species is native to the Gulf of Mexico, from northern Mexico to Florida. It has been deliberately introduced in countries of Asia, Africa and Europe. It is interesting the case of this species in the south of the European continent, where it has expanded and has colonized new territories, displacing the native river crabs.

However, it is not true that the American river crab eat the Iberian crab, or that the aggressiveness and larger size of the exotic has displaced the Spanish. The cause is the existence of a fungus, Afanomicosis astaci, for which the autochthonous crab does not have antibodies. The American river species are carriers of a fungus with which they live and does not cause any problem for them; but it is deadly for the Iberian species. When the American crab reaches a river, it contaminates the waters with the spores of the fungus and causes the death in the populations of native crab.

red crabs: gulf of mexico

 Red Crabs Economic Importance

The rapid growth and great adaptability of the  P. clarkii, has promoted the industry of this crayfish in Louisiana, which generates millions of dollars per year, with more than 500 km² of crops of this species. The P. clarkii makes up the vast majority of crayfish production in the United States and other countries.The american red crab has also been introduced for breeding in different countries such as Spain, where its success is attributed to its ability to adapt and colonize altered habitats that would be unviable for the native crayfish.  Finally, it is also important to know, that they are bred for being used in teaching and research.

Red Crabs as Food

This topic can be very provocative for some people, and there are even some who prefer not to talk about it. However, it is necessary to tackle it, since there are many places in which the red crab is considered their favorite dish.

Now we will know those places.

In Nigeria for example, the red crab is a main ingredient of the traditional dish of that country. Before eating it, this crustacean is usually placed for a few hours under the sunlight to soften it.

In Mexico, the red crab was a very important food source in antiquity, and today, it is still consumed with many sauces and very well-seasoned.

In the United States, the red crab is fully cooked in a pot, adding many condiments. Then they enjoy this exquisite dish on different occasions such as meetings or holidays.

In Spain there has been a large decline in the population of this species due to environmental pollution. At present it is prohibited to hunt the red crabs in that country.For this reason its consumption has been replaced by that of marine crabs.

In Sweden, red crabs are a traditional dish and are consumed completely cold.

Red Crabs´ Prohibition of  Commercialization

As we have mentioned, in Spain the commercialization of the red crab came to be strictly prohibited, leaving all its inhabitants surprised. The idea was promoted by the Ecologists in Action Foundation, to expand the Spanish Catalog of Invasive Species approved in 2013..

This decision drastically affected the inhabitants of Isla Mayor (Seville), a town in which three of every four people live off the fishing and commercialization of this crustacean.

This has even caused the migration of many people from these localities, in search of different economic activities.

The red crab was artificially introduced in the 70s, and is known to invade the area of ​​native crabs.

Ecologists claim that this species is lethal to the population of other species of crabs in the area, and that they have drastically altered the environment. Red crabs have even depleted species, such as some amphibians, invertebrates and birds that depend on the ocean floor, an area that the red crab eliminates. Therefore, the best way to control this situation is through the complete eradication of this crustacean.

But those of the sector did not remain calm, and they raised all their restlessness  to the court that imposed the sanctions to them.

Reaction of those affected

Many residents of Isla Mayor alleged that they are left without life, since their families are dedicated to fishing and marketing these crabs. Almost 70% of the population of this town lives from this activity, and without it the town of Isla Mayor goes directly adrift.

No one imagined that this species would generate so much wealth for such a small town, and that the decision would take away from one day to the next, its only sustenance.The red crabs became the theme of the day of this town of 6000 inhabitants, but in a different way.

The majority of its inhabitants faced the worry of having to migrate to another state or country, in search of employment.

Control of Red Crabs: The suffering is over

Finally this year the reform was repealed. Spain softened the fight against certain exotic invasive species. The commission of Agriculture and Environment of the Congress approved on April 14, 2018, various modifications of the law of Natural Heritage that open the door to certain exotic invasive species, which until now had to be eradicated, so they can be exploited (hunted or fished, released or encouraged).

The softening of the current legislation was made concrete through a new legal figure: the naturalized invasive exotic species, which alludes to the specimens that were introduced without a prior express prohibition, in which it is not fully demonstrated that they cause ecological damage and that they have an economic interest.

Thanks to the court’s new decision, the inhabitants of Isla Mayor recovered their smile. Now they do the same activity, but this time with more recognition, since they are legal. The only change that generated this decision is that they cannot market the live red crab. The losses generated in this respect are insignificant compared to what it meant to stop doing the activity they know best.

Their next goal is to be all professionals in the field, and the sector has machinery, to make the work a little easier, but that will be achieved little by little, and above all with much effort.

The decision provoked the protest of the environmentalist foundations, and at this moment a balancing action is being sought to protect the work without harming the ecosystem.

Red Crabs as Pets

First we must emphasize that they eat many fruits, vegetables and different types of meat. So that they can drink water, it is necessary to put a sponge with water, which can absorb as much water as possible. From time to time it is necessary to wet them in fresh water and at room temperature.

The good thing about red crabs, is that they can withstand different ranges of temperatures, either high or low, in the place where you are going to have them. You can make them a kind of cave, with leaves or sticks, so they can get in when they want.

In order to make a habitat comfortable enough for them, you will need a large enough fish tank. In one corner of this container, you must place a vessel where he will drink water.

It is advisable to buy land in a nursery. A small bag will suffice  to put it in the terrarium of the crab. Once you have it, you should spread it everywhere; have plants on hand to place them in places so that the crab can feel better, as if it were in its natural habitat.

Keep in mind that red crabs are very shy with humans, and it’s something you can appreciate if you try to grab them. They usually hide in bushes, rocks, and trunks, and that is why it is always recommended, put something, so they can hide.

Final Considerations

Knowing everything about the red crabs, we realize that in some countries of the world are really necessary, because thanks to them, many people can work and live.

Although it is a species, which is considered dangerous for some habitats, the only option they have is to control their existence.

Another point to highlight, is that many people enjoy having them as pets, and in the article, it was possible to appreciate all the care that should be taken into account. To enjoy them, it is necessary to understand that you can not have an animal because you have it, it is of vital importance, that you have a commitment, and that you take good care of it.

Now, let´s enjot this funny video

Deja un comentario