Japanese Spider Crab

The Japanese and European Spider Crab spiders or spider crabs fall under the Crustacea class. If you’re interested in learning about a crab that has some interesting features, then you are reading it right now! The family Madijae has seven hundred marine species of crabs. If you look at their exoskeleton, you will find that it bristles. Their legs are also long.

This is one of the main reasons as to why they are known as the spider crab. Below, we are going to take a look at the Japanese and European Spider Crab. We believe you will be more interested in the Japanese Spider Crab because it has many interesting features.


Most of the spider crabs you see will have thick, rounded bodies. They are slow animals and don’t move as fast as spiders do. Mostly, they are scavengers who eat dead fish. Dead mollusks and dead starfish are in their diet. They are not only found in the Atlantic but the Pacific regions as well. Some of the crabs prefer the muddy regions, but there are others that prefer rocky substrate.

Japanese Spider Crab

The sizes will range anywhere from twelve mm to four m. Have you ever looked at their legs and their shell? It is covered with setae. The spider crab is dimorphic. After they mate, the female will store the sperm in what is known as her spermatheca. One time of mating equals to a couple of subsequent fertilization.

Maja Squinado

There is the Maja Squinado, which is also known as the European spider crab. It is found in regions where the seabed is soft. The crabs partially bury themselves in the substrate. It is normal to come across the adult males in the areas where there is a rocky seabed. The European spider crab can live anywhere from five to eight years. It goes through the larval stage, which is followed by the juvenile stage before it turns into an adult.

The adult crabs adapt to eating a variety of different foods. The main part of their diet consists of marine algae. They have a unique feature where they can copulate, even if the female is hard. This is unique because a lot of the other species of its phylum will require the female crab to exuviate before they are able to mate.

These spider crabs are found in the northeastern parts of the Atlantic as well as the Mediterranean Sea. Did you know that they migrate seasonally? This is a feature that many individuals find interesting. They migrate during the autumn months and can cover one hundred miles in as little as eight months.

Biggest living arthropod

You also have the Macrocheira kaempferi, which is known as the Japanese Spider Crab. This is the biggest living arthropod out there. It has a body size that is around thirty-seven CM and can weigh up to twenty kilograms. Would you believe that it can live for up to one hundred years?

This really is an amazing lifespan, considering the fact that the European Spider crab only has a lifespan of five to eight years. The Japanese Spider Crab got the name after Engelbert Kaempfer. Engelbert Kaempfer is a naturalist and traveler.

This crab has an orange body with white spots appearing on the legs. They also have compound eyes that have two horns poking out from between them. If you are interested in seeing the Japanese spider crabs in a natural habitat, then you would have to go to the Pacific region in Japan.

Spring season

Normally, they live as deep as one hundred and fifty to eight hundred meters down in the seabed. The spring season is important to them as this is the time they lay their eggs. Many eat these crabs and use them for ornamental purposes. (Read our article on how to catch crabs.) Apart from it all, they are also used for research.

Today, you will find that these crabs are decreasing in population, and efforts are currently being taken in order to protect them. Have you taken a look at this type of crabs? If you are afraid of spiders, then you will more than likely be afraid of these. The Japanese Spider Crab has the largest leg span of any other arthropod. Could you imagine how that looks?

They have a fierce look, yet they are still the creation of nature, so we respect them. It has also been said that they have a gentle disposition, which is hard to believe because they look so fierce. Despite the appearance that they have, they still have a right to be protected out of harm’s way. It is better that they are protected and not become extinct. While you’re here read this article on European Green Crab.