This post will focus on explaining how crabs interact with their peers, humans and other biological organism. Along with that the molting process is discussed.
Molting
The molting process occurs in crabs and other crustaceans, where they shed their shell in order to grow. Crabs cannot grow in a linear fashion, this is due to that their body is surrounded by a hard shell that does not grow. Prior to the molting process, crabs absorb calcium carbonate from the old shell, then they secrete enzymes to separate the underlying skin (epidermins) from the old shell. After this, the epidermins generates a paper-like soft shell beneath the old one [1]. A day before molting, crabs absorb water and ions into their circulatory system to swell up its body, thereby allowing the outer shell to expand and be cracked [2]. The crab then extracts itself by compressing and pushing all of its appendages. This process takes about 15 minutes [1]. Once the crab is out of its old shell, the crab begins to harden its new shell by absorbing calcium from the water [2].
The crab during molting removes legs, eyestalk, mouthparts and the gills along with him leaving behind the old shell, esophagus, entire stomach lining, and the last half inch of its intestine [1]. Crabs may molt 15 – 20 times during their lifespan [2]. The molting process has other benefits beside growth, such as getting rid of parasites, barnacles, bacteria degrading the chitin and other animals growing on the shell [1]. However, the molting process remains very dangerous and stressful. During molting the crabs will be at the risk of cannibalization by other crabs or vulnerability to other predators. Even small physiological, mechanical or chemical problems may result in a certain death [2]. Crabs that have lost legs can regenerate them during molting. Crabs need three molts to grow their leg back to its normal size [1]. The table below shows the frequency of molting thought-out the lifespan of a king crab.
Table. 1: Molting Frequency At Specified Years [1]
The crab during molting removes legs, eyestalk, mouthparts and the gills along with him leaving behind the old shell, esophagus, entire stomach lining, and the last half inch of its intestine [1]. Crabs may molt 15 – 20 times during their lifespan [2]. The molting process has other benefits beside growth, such as getting rid of parasites, barnacles, bacteria degrading the chitin and other animals growing on the shell [1]. However, the molting process remains very dangerous and stressful. During molting the crabs will be at the risk of cannibalization by other crabs or vulnerability to other predators. Even small physiological, mechanical or chemical problems may result in a certain death [2]. Crabs that have lost legs can regenerate them during molting. Crabs need three molts to grow their leg back to its normal size [1]. The table below shows the frequency of molting thought-out the lifespan of a king crab.
Table. 1: Molting Frequency At Specified Years [1]
And this an interesting video for the molting of a rainbow crab. All the credits go to the owner of this video.
Interaction
In normal circumstances, crab usually do not interact with their own species. The only time is when they are fighting for food which is discussed in previous post. The video below shows how the adopted pet interact with each others and to the environment. They were put into a big tank to allow more space to move so to make this investigation more successful. When they sensed harm from the environment, they will run away to hide because of their naturally coward creature. Sometime they will sit on each other to find comfort.
They do not like to be moved around and being disturbed. These pet will form bubbles in their mouth due to over excitement from the environment which shocked them. Therefore, it is important to minimize movement of their living habitat and touching them.
They do not like to be moved around and being disturbed. These pet will form bubbles in their mouth due to over excitement from the environment which shocked them. Therefore, it is important to minimize movement of their living habitat and touching them.
[1] D. B. G. Stevens. (18 May). Molting: How Crabs Grow. Available: http://www.afsc.noaa.gov/Kodiak/shellfish/cultivation/crabGrow.htm
[2] A. R. G. a. J. A. Anderson, "Soft Shell Crab Shedding Systems," SRAC Publication 4306, October 2011.