Butter crab
As Butter cancer is called crayfish or other large crustaceans that have recently skinned. The cuticular exoskeleton of these crabs, which consists of chitin with calcium deposits, is still very soft and elastic in this phase. After the moulting process, it is first brought into its final shape and size by absorbing water and slowly hardens. The color of the not hardened shell is light, partly yellowish and it is soft like butter , which gave the crabs the name butter crab at this stage.
Stripping off the old armor only takes around 15 minutes, or a little longer if there are complications. If the old skin cannot be shed during this time, the cancer usually dies of exhaustion afterwards. The hardening process of the new protective layer takes three to four days, during which lime from the " gastroliths ", the calcareous stomach stones of cancer, has to be transported into the soft chitin armor. These concretions , also known as "cancer eyes", are formed in the cancer stomach and serve as intermediate storage for the minerals that are necessary for the formation of the new shell.
The buttercup is easily vulnerable during this period and endangered by its predators; he withdraws between stones or in a cave. Anglers and sport fishermen are specifically looking for crayfish as bait, because they attract many fish from roach to carp to eel . Butter crabs are also easy prey for other crabs, which animal owners can often observe in aquariums . As a stress reaction, crabs and crabs in this situation often shed several limbs after molting if there is a threat from their fellow species.
Since the exoskeleton on the legs of the buttercup is still soft, the locomotion of the buttercup is completely different than after the molt has been completed. All legs move in the same direction from back to front, thus moving the animal forward. This is necessary to find a hiding place after dropping the old tank.
In a figurative sense, sensitive, spoiled or inexperienced people or small children are also called “buttercreams”.
literature
- Heinrich Kühl: Observations on the plasticity of the nervous system in long-tailed crabs (lobsters, crayfish) . In: Pflüger's archive for the entire physiology of humans and animals . tape 229 , no. 1 . Springer, Berlin / Heidelberg 1932, p. 636-641 , doi : 10.1007 / BF01754495 .
Web links
Individual evidence
- ↑ Elisabeth Licek: Armored Knights: Crayfish in Austria . Uni Vet Vienna Report, 3/03, March 2003, p. 8 ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. (PDF)
- ^ Cancer molt
- ↑ Angelblogger ( Memento of the original from March 13, 2008 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (German)
- ↑ Mouth mixing: butter cancer in the figurative sense
- ^ Butter crab. In: Jacob Grimm , Wilhelm Grimm (Hrsg.): German dictionary . tape 2 : Beer murderer – D - (II). S. Hirzel, Leipzig 1860, Sp. 585 ( woerterbuchnetz.de ).
