2023-12-01 07:36:00
Many crabs die in the fall. On the beach they lie along the waterline. There always seem to be a lot of dead crabs washing up, but that’s not true. A crab grows out of its shell and must molt from time to time. That is the old, narrow scale. Empty back shells more often mean a growing crab than a crab in its grave. In shellfish, the shell is attached to the mollusk. The animal hatches from the egg with a tiny shell and sculpts edge after edge itself. Shedding is not necessary.
Crustaceans and shellfish are often mentioned in the same breath. Yet they are as related to each other as an earthworm is to a human being. That is why it is surprising that so many people believe they are allergic to both completely different animal groups.
Multiseksueel
Shellfish have a versatile sex life, as can be read in my shell book Northern clams, sea angels and coffee beans. Shellfish can be female, or male, or both at the same time, or they start out as male and later become female. Name a variant and shells do it: you could call them multisexual.
Crabs also like porridge from it. Beach crabs, the most numerous crab on the North Sea beach, are either female or male. A shore crab holds its genitals against its abdomen with a tail that acts as a cover. During times of action, the valve opens. It is shaped like a beehive in females and a pointed triangle in males – an easy to remember characteristic. If you find a dead crab that is still intact, you can pull that valve open. You should definitely not do this with a living person; then you are guaranteed to damage something. If it is a male, you will see two thin so-called sperm legs under the valve. You don’t see any genitals on the female. Only when mating takes place does she bring her two sperm chambers into position. It is unknown whether four orgasms can be achieved simultaneously during stereo sex.
Three times a week, biologist Koos Dijksterhuis writes about something that grows or blooms. Read his previous Nature Diaries here.
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#Beach #crabs #stereo #sex #Fidelity