The Sun-Absorbing Self-Decapitator

by Jammy-Adrienne Valerio, Reporter

Science

The title may sound reminiscent of the mythical phoenix: the bird with sun-like flames for feathers, the symbol of rebirth from mere ashes. However, the creature of today’s topic is neither a bird, nor does it relate to fire of any kind.  It resides solely in the sea, and instead of ashes, these animals come back to life from their own decapitated head. Sounds unfamiliar? Well, let's pull back the curtains on this creature, and show the real truth.

Meet… The leaf sheep slug. 

Not exactly what you imagined? Fear not, there’s more than meets the eye. Costasiella kuroshimae, or leaf sheep slugs, are part of the class of Gastropoda, which includes snails and slugs. They get their name from their white head, beady eyes, and black rhinophores (the things that stick out from their heads) that look like sheep ears. They’re under the superorder of Sacoglossa, of which there are 284 known species worldwide (Schuster). Leaf sheep slugs are one species of Sacoglossa that have no shell and lay their eggs in a cute spiral pattern. Sacoglossans, however, are capable of peculiar powers that make them unique, which the leaf sheep slug is capable of showing.

Immediately striking is the slug’s vibrant green coloration that looks a lot like lettuce. The color actually comes from the food they eat, which is mainly algae. Using one row of teeth, they suck in the plasma from the plant and digest the food parts, but keep chloroplasts undigested (Schuster). Chloroplasts store chlorophyll in their cell bodies, which is vital for plants to undergo the process of photosynthesis — where sunlight is turned into usable energy. Chlorophyll is also responsible for turning plants green, which is why most Sacoglossans, including the leaf sheep, are colored green. Leaf sheep slugs isolate and imbed chloroplasts into their own tissue, which means that the slug is able to utilize the energy created from photosynthesis for itself. This process is called “kleptoplasty,” which means “to steal chloroplasts.” These slugs are able to keep the chloroplast for months, which means they’re able to rely solely on  sun-powered energy like a solar panel (The Octopus Lady)! Sacoglossans are the only multicellular species to be successful at kleptoplasty; all others are unicellular. It turns out that the phrase “you are what you eat” is true for Sacoglossans after all.

Becoming part plant isn’t the only superpower leaf sheep and Sacoglossan slugs are capable of, they can also divide. Specifically, leaf sheep slugs are capable of separating their heads from their bodies. There are some species of lizards that are capable of detaching their limbs in the face of a predator, a process called “autotomy” (Schuster). Autotomy is the conscious ability for an organism to self-amputate itself, usually when threatened. Unlike lizards’ tails, the head is fully functional after the beheadings. Not only does the decapitated head continue to live after ditching all its vital organs in its body, but the head is able to feed on algae after a couple of hours, and can even regrow its full body — forgotten organs and all (Readfearn). Researchers speculate this process occurs to get rid of parasites within their bodies, and that kleptoplasty is the reason they’re able to create new cells. Still, is that not a pretty metal way to get rid of invaders within the body? Imagine humans ripping their heads off after a strong infection, and then regrowing all the bones and organs back.

The world is home to millions of unique organisms with strange yet fascinating abilities. Though mythical creatures like the graceful phoenix may not exist, leaf sheep slugs do. As living plants and professional dividers, leaf sheep slugs make for one more interesting tale to tell around friends. It’s like the oral myths of yore, except this whimsical creature is all true. 

DISCLAIMER: The opinions, beliefs, and viewpoints expressed by the various authors in this paper do not necessarily reflect the opinions, beliefs, and viewpoints of Kamiak High School or The Gauntlet. 

Sources

 Readfearn, Graham. “Keep Your Head: The Self-Decapitating Sea Slugs That Regrow Their Bodies – Hearts and All.” The Guardian, 8 Mar. 2021. The Guardian, https://www.theguardian.com/environment/2021/mar/08/keep-your-head-the-self-decapitating-sea-slugs-that-regrow-their-bodies-hearts-and-all.

“Sacoglossa.” Wikipedia, 17 Oct. 2023. Wikipedia, https://en.wikipedia.org/w/index.php?title=Sacoglossa&oldid=1180595265 .

Schuster, Ruth. “Meet the Self-Decapitating, Deep-Sea Version of Shaun the Sheep.” Haaretz. Haaretz, https://www.haaretz.com/science-and-health/2021-12-02/ty-article/meet-the-self-decapitating-deep-sea-version-of-shaun-the-sheep/0000017f-f7da-ddde-abff-ffff0a940000.  Accessed 19 Oct. 2023.

The Octopus Lady. “These Sea Slugs EAT SUNLIGHT and RIP THEIR OWN HEADS OFF 🤘🔥🤘 | Alien Ocean.” YouTube,  www.youtube.com, https://www.youtube.com/watch?v=Jm7nZMHX2Cs . Accessed 19 Oct. 2023.