Natures wonders:carnivorous sea slugs, weird! (Introduction)

by David Turell , Tuesday, November 15, 2016, 01:40 (2929 days ago) @ David Turell

This article includes a great video:

http://www.livescience.com/56841-carnivorous-sea-slug-video.html?utm_source=ls-newslett...

"M. viridis, which can reach up to 5 inches (13 centimeters) in length, is unusual-looking, to say the least — its body texture resembles a wad of leafy greens that has been partly chewed and then spit back out. The individual in the video appears to have seven pairs of oar-shaped limbs, with the biggest ones close to the front of its body and the smallest pairs closest to its tapering back end.

"But the creature's most striking feature by far is a large, balloon-like sac at the front of its body, which it uses to catch crustacean prey by casting the loose folds like a net to engulf its meal. M. viridis gulps down its prey and ingests it whole, scientists have found — dissections of several specimens revealed intact crabs in the nudibranchs' stomachs.

"In the video, though the nudibranch's body doesn't move much, its "head" repeatedly extends forward and flattens on the seafloor while the oral opening gapes wide, searching the ocean bottom for tasty morsels like shrimp or tiny crabs. Sensory structures line the edges of the opening; when these hairs touch the nudibranch's prey, the sack contracts and traps the prey inside, where it is ingested.

"And if you think nudibranch feeding habits look strange, nudibranch sex is even weirder.

"Nudibranchs are hermaphroditic, possessing both male and female sex organs. But instead of self-fertilizing as some hermaphroditic animals do, nudibranchs exchange chemical signals during mating to determine which of the pair will assume the female role.

"And for a nudibranch, that can involve amputating a disposable penis or stabbing its mates in the brain with genital darts."

Comment: As a part of the balance of nature, this animal cleans the ocean floor of tiny crustaceans like a vacuum cleaner. Everyone has to eat something.