The legend of the house slave of the hermit crab, not only must gather in line to change houses, but also the mating tools must "mutate" the house.

In addition to humans, there is a creature in nature who values ​​the "house" quite seriously. For them, the "house" was not only the lifeblood, it even changed the direction of its evolution.

A new study found that they also evolved a long tintin specially to prevent the house from being taken away when it was impossible to describe it. When there is no need to bear the pressure of the "house", they have no incentive to evolve long tintin. This creature is a hermit crab.

It is bitter that hermit crabs living so hard are now forced to settle in plastic garbage because they cannot find a suitable "house".

Although there is a crab character, hermit crabs and ordinary crabs are two different species. The hermit crab is the general name of the hermit crab family and the hermit crab family of the arthropod crustacea Decapoda.

The crab we are familiar with belongs to Brachyura, which means a decapod crustacean with a short tail and a pair of limbs and eight legs. In simple terms, crabs are crustaceans with short tails.

Although the hermit crab also has a pair of strong áo limbs, its carapace is not as hard as the shell of a normal crab, especially the abdomen is very soft.

So in order to protect themselves from harm, they must find a harder conch shell to protect themselves. We can compare these conch shells to the houses where they live.

Hermit Crab Curved Belly

Hermit crabs patiently look for snail shell creatures, then kill them and tear the snail meat to eat. After that, he drilled the back half of his body into the empty shell, and hooked the empty shell of the conch with the last pair of abdominal limbs.

In this way, they succeeded in living in the new house they had snatched. Since the "house" was owned by someone else, they had to walk around with the "house" grabbed every day, so that their right and left chelates became asymmetric.

This is not over yet, as they continue to grow, they need larger housings, so they need to change houses every so often. Spirulina are ultimately limited resources, so fierce competition often occurs among hermit crabs.

Hermit crab retracted into the shell

Generally speaking, hermit crabs who grab a house will use sharp sharp claws to clamp the original owner. Then, it used its own shell to hit the shell of the original homeowner until it knocked over.

At this time, the house grabber will first stop and observe the attacker's opponent's shell to see if it is in accordance with his own wishes. If it's fancy, they will ruthlessly push the original homeowner out of the shell and move into it. The hermit crab who lost the house can only reluctantly pick the victor's abandoned shell to live in it.

However, some scientists believe that hermit crabs may rob a house in order to maximize the use of resources, which can be regarded as a mutually beneficial behavior between animals. Because screw shells are like hermit crabs, fitting is the most important thing.

If a large hermit crab lives in a small spiral shell, it is more crowded, and a small hermit crab lives in a large spiral shell, which adds to the burden of walking. Therefore, if after the two meet, it is better to simply buy a second-hand house.

Hermit crabs fighting over the house

With the continuous decrease of spiral shells, hermit crabs have also evolved the mutually beneficial behavior of gathering people to line up for houses. When a hermit crab finds a new house, it leaves its shell to check the size of the house.

If the shell is found to be too large, the hermit crab will return to its shell and wait in place. When a new hermit crab arrives, a similar action is repeated. Finally, they form a team of 10 to 20 hermit crabs. Immediately after, they will line up from the largest hermit crab to the smallest hermit crab, lined up in order to change rooms.

It was not until the smallest hermit crab had completed the "house" change operation that everyone left. Such an orderly house change operation can't help but marvel at the survival wisdom of hermit crabs.

Some land hermit crabs also secrete corrosive chemicals to decorate their houses. In this way, some internal structures in the spiral shell will be removed and become more spacious. The extra space can also be used to store eggs, and it is also lighter to carry.

Such a carefully remodeled house will become very sought after, and other hermit crabs will be jealous of it. The homeowner had to stay in his house at all times.

But when hermit crabs mate, male hermit crabs must leave their shells. Only when the two crabs stand together in an open-faced manner can a male hermit crab shoot a small tadpole into the shell of a female hermit crab.

Hermit crab leaving the shell

How can I keep my house while mating? The first is to shorten mating time. The mating time of land hermit crabs is indeed shorter than that of marine hermit crabs, which are easy to find shells.

Mark Laidre of Dartmouth conjectures that the Hermit Crab Lu seems to have evolved a longer tintin to protect his house. This way they only need to stick out important parts while mating, while most of the body remains in the shell.

This interesting result was obtained by Leder measuring the penis-to-body ratio of 9 different land hermit crabs. He found that in some cases, the crustacean tintin was even more than half its body length. The hermit crab, which has a carefully "remodeled" house, has a higher body weight ratio.

A specimen of a male C. compressus. The length of the penis is shown by the red arrow. The abdomen of the hermit crab is on the left and its feet are on the right.

For example, the Siberian Hermit Crab (Coenobita clypeatus) hardly remodels a shell, and its body ratio is about 30%. The orange-red land hermit crab (Coenobita perlatus) will slightly reshape its shell, and the body-to-body ratio is about 50%. The Ecuadorian hermit crab (Coenobita compressus) has the most decoration efforts under the shell, and the highest body weight ratio, reaching 60%. As a control, the human body weight ratio is about 7-8%.

Hermit crabs that do not require a shell have the shortest penis of these three types, which is the coconut crab (Birgus latro). Before adulthood, it carried the picked shell like other hermit crabs, and by the time of adulthood, it formed a hard shell, thus abandoning the house and living a stray life. Studies have found that the penis length of coconut crabs is less than 20% of the body.

Therefore, Leder believes that Tintin has become shorter without the pressure of a house. And this new research for the first time suggests that valuable private property may also become the selection pressure of animal tintin evolution, changing human cognition.

Coconut crab

Even so, they cannot avoid the harm of other animals. For example, octopus often uses its flexible and powerful wrists to drag hermit crabs out for a full meal.

So for the sake of safety, some hermit crabs chose symbiosis and they found anemones as neighbors. Anemone is a coelenterate animal that is bright and flowery but full of spiny cells and secretes venom. There is just an anti-toxic substance in the blood of hermit crabs, which can prevent the anemone from harming it.

Therefore, hermit crabs would walk around carrying anemones, making fierce enemies afraid to prey on hermit crabs. Whenever a hermit crab wants to change the "house", she will not forget to bring Shanghai sunflower.

About 150 million years ago, the ancestors of the hermit crabs started the hermit model, relying on screw shells to protect themselves.

As the so-called peace and security are in danger, the spiral shells in the ocean continue to decrease, and the ancestors of parasitic crabs begin the process of crabbing.

According to the latest DNA analysis evidence, crab-shaped and armored shrimp-shaped animals have evolved multiple times from the ancestors of hermit crabs. In other words, king crab and armored shrimp are two creatures with very different shapes, and their initial shapes are similar to hermit crabs. . This also shows that the body structure of hermit crabs is very flexible and they have evolved in parallel to different crab-like forms.

Although the porcelain crab family to which the anemone crab belongs has the appearance of crabs, it actually belongs to the armored shrimp family, and its relationship is closer to the armored shrimp and hermit crabs.

At first glance, king crabs look a lot like crabs, but they have only six legs and are classified as Anomura. It is also known as Crouching, and it is a taxonomy under the crustaceans of the Decapoda, including hermit crabs, porcelain crabs, armored shrimps and inferior column shrimps, stone crabs and so on.

Most of these creatures have the word "crab" or "shrimp", but they are different from the species that are collectively referred to as crabs, shrimps, and langoustines. Common crabs belong to the short-tailed order, while ordinary shrimps belong to the real order. King crabs look like crabs because of parallel evolution. That is, the individual evolution of similar features, there is no close relationship between the two.

For hundreds of millions of years, the ancestors of the hermit crab survived many difficulties and survived, and carried forward the family. As everyone knows, due to human damage to the natural environment, many hermit crabs cannot find a suitable shell and are forced to live in plastic garbage (such as bottle caps). There are news reports that 570,000 hermit crabs have been starved to death because they found the wrong new "house", which is regrettable.

Some scientists believe that this is likely to be an important reason for the decline in hermit crabs. Who would have thought that the plastic bottles discarded by humans would easily wipe out the clever hermit crabs.