Get smart curated videos delivered to your inbox every week.      
The Kid Should See This

The sea cucumber’s multipurpose rear end

Is it a fuzzy sock? An overripe banana? A moldy tube of toothpaste? No! In fact, it’s a humble sea cucumber: a brainless, fleshy form surrounding a digestive tract, and bookended by a mouth and an anus. And while it might look odd, its daily toil paves the way for entire ecosystems to thrive.

How? Sea cucumbers are underwater vacuum cleaners, filtering the sand of algae and waste particles as they ingest it and poop it out. This improves the ocean floor for seagrass beds, corals, and shellfish, and likely fights ocean acidification.

sea cucumber
But this cheeky TED-Ed by Cella Wright, titled The Most Important Anus in the Ocean, also reviews the creature’s multipurpose rear end. For example, some sea cucumbers breathe with their anus. Others eat with it. It’s where they reproduce. And still, others expel their regenerative, sometimes toxic guts to surprise and defend against predators.

sea cucumber defenses
hiding fish
For the pearlfish, the sausage-shaped echinoderm’s rear end can be shelter. This BBC clip with marine biologist Dr. Helen Scales provides some further detail:

Watch more echinoderm videos, including this very important follow up: The benefits of sea cucumber poop.

This award-winning video collection is reader-supported. Become a sustaining member to keep TKSST online and free for everyone, including teachers and parents who use it as a resource to spark learning and curiosity for kids.