Saturday, March 11, 2023

The Cockroach Catcher II: Attempted Living---Kibbutz & Memory



Nudibranch


Kibbutz & Memory


Eric Kandel 


..........One night we were having dinner with a very interesting couple. The husband was aiming to climb the Matterhorn and somehow in the conversation he revealed that his other passion was in the other direction, diving.   When he dives, his favourite things to see are these beautiful shelless sea slugs.

“Nudibranch!”  I showed him some photos I had on my phone that were taken by my diving friend. Snorkelers are not going deep enough to see these beautiful creatures!

Here is a description in The National Geographic:

Nudibranchs crawl through life as slick and naked as a newborn. Snail kin whose ancestors shrugged off the shell millions of years ago, they are just skin, muscle, and organs sliding on trails of slime across ocean floors and coral heads the world over.

Found from sandy shallows and reefs to the murky seabed nearly a mile down, nudibranchs thrive in waters both warm and cold and even around billowing deep-sea vents. 

So why, in habitats swirling with voracious eaters, aren't nudibranchs picked off like shrimp at a barbecue? The 3,000-plus known nudibranch species, it turns out, are well equipped to defend themselves. Not only can they be tough-skinned, bumpy, and abrasive, but they've also traded the family shell for less burdensome weaponry: toxic secretions and stinging cells. A few make their own poisons, but most pilfer from the foods they eat. Species that dine on toxic sponges, for example, alter and store the irritating compounds in their bodies and secrete them from skin cells or glands when disturbed. Other nudibranchs hoard capsules of tightly coiled stingers, called nematocysts, ingested from fire corals, anemones, and hydroids. Immune to the sting, the slugs deploy the stolen artillery along their own extremities.

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