TNB Night Owl – Anemones versus Sea Slugs

Various examples of sea anemones (1893 print by Giacomo Merculiano). Public domain {{PD-US-expired}}.

Like octopi and squid, sea anemone (ə-nĕm′ə-nē) and sea slugs are so different from humans they may as well be alien creatures from other worlds – which makes them all that much more interesting. Upping the drama, many ocean creatures are both predator and prey: when two predators meet, one of them is likely to lose.

Sea anemones are named after the terrestrial flower, as they come in many different colors and shapes, depending on the species. Related to corals, hydra, and jellyfish, sea anemones are also closely related to tube anemones, the significant difference being the latter live in tubes and have the ability to withdraw themselves and their tubes into soft ocean floor sediment in an attempt to escape attacks. A crown of tentacles at the top of the animal consists of two ‘whorls’. The outer whorl is primarily employed to capture prey, while the inner whorl of tentacles is used to ingest the prey. Typically, they’ll eat most anything that happens to come within reach of their tentacles.

Scientific Classification
(of tube-dwelling anemones)
Kingdom: Animalia
Phylum: Cnidaria
Subphylum: Anthozoa
Subclass: Ceriantharia
Genus: several
Species: several

There are also numerous species of sea slugs, many of which are colorful and exotic in appearance. The blue sea dragon is a good example (short video below), spanish dancer is another. They can be cannibalistic, but they love anemones for breakfast, lunch, and dinner. They’re often referred to as nudibranchs, a name derived from their order, Nudibranchia.

Scientific Classification
(of sea slugs, a.k.a nudibranchs)
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Subclass: Heterobranchia
Infraclass: Euthyneura
Subterclass: Ringipleura
Superorder: Nudipleura
Order: Nudibranchia
Genus: several
Species: several

Now, on to the gratuitous predator versus prey videos.

“Facts: The Blue Sea Dragon” (1:55)

“Sticking finger into Sea Anemone” (0:31)

“Tube Anemone attacked by Spanish Dancer” (1:40)

“Giant Nudibranch vs Tube Anemone” (0:51)


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About Richard Doud 390 Articles
Learning is a life-long endeavor. Never stop learning. No one is right all the time. No one is wrong all the time. No exceptions to these rules.