These Horrifying Sea Slugs Smell Like Watermelon Candies. (Part 2)

             Those are called cerata, and yes, they’re weird especially since slugs can just discard them at will when they need to escape a predator, a phenomenon called autotomy. But even those paddles aren’t their weirdest trait. What makes hooded sea slugs unbelievably bizarre is the watermelon smell. Yes, much like a Jolly Rancher or a scented candle, these sea slugs have a fruity, watermelon scent. YouTube hasn’t figured out Smell-o-Vision, เกาะหลีเป๊ะ ที่พัก ราคาถูก so you’ll have to trust me on this:  They, for real, emit a melon-y odor. And that’s thanks to a terpenoid.

             Even if you don’t know the word “terpenoid,” you’re probably fond of many of these smelly, usually plant-derived chemicals. They’re what give ginger that gingery flavor, and why pine trees have that   wonderful, wintery smell. And one called melon heptanal, melonal, or 2,6-dimethyl-5-heptanal, เกาะหลีเป๊ะ ที่พัก ราคาถูก if you want to be technical, is distinctively melon-y. In fact, we use a synthetic version of this exact chemical in artificial melon flavors and scents. And lion’s mane nudibranchs can emit it to deter their enemies. Apparently, undersea predators like sea stars just aren’t as into melon-scented stuff as we are.

             Now, using terpenoids defensively is something other nudibranchs do, too. But they usually get their noxious substances from the things they eat. Hooded sea slugs can’t really do that, since as far as we know, เกาะหลีเป๊ะ ที่พัก ราคาถูก none of the slugs’ prey produce melonal.

             And last I checked, they don’t have an assortment of fake watermelon candies to snack on, either. So, they make it themselves in special repugnatorial glands. Then, since their predators flee from the fruity scent, the slugs can feel safe scooting about and wrapping those adorable oral hoods around little invertebrates to digest them alive.