# Sea slug can chop off its own head and then regrow its body **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [March 8, 2021, 9:24pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476 "2021-03-08T21:24:55Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [March 8, 2021, 9:24pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/1 "2021-03-08T21:24:55Z")
> **[This sea slug can chop off its head and grow an entire new body, twice](https://www.livescience.com/decapitated-sea-slugs-regrow-entire-body.html)** > > It is one of the "most extreme" examples of regeneration ever seen. Pretty amazing. These guys can sever their own heads. Then the head crawls around for a few weeks as it grows a new body. They may discard the body to get rid of parasites, which seems pretty extreme to me. They may be able to survive because they have algae in their skins that provide nutrients while they grow a new digestive system. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [March 8, 2021, 9:29pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/2 "2021-03-08T21:29:13Z")
Fascinating, in an eldritch horror sort of way. But isn’t it more like chopping off its body? ---
**Author:** ![bobot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bobot/32/21622_2.png) [@bobot](https://boards.straightdope.com/u/bobot)\ **Post date:** [March 8, 2021, 9:52pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/3 "2021-03-08T21:52:20Z")
Yeah, if a new head sprung up out of the old body, It would seem that they cut off their heads. What worries me is a rash of copycats by impressionable dumb people. I haven’t read the article yet, but I hope it is made explicitly clear that this does not work on people! ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [March 8, 2021, 9:59pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/4 "2021-03-08T21:59:01Z")
Fascinating indeed. I would like to be able to do that. ---
**Author:** ![bobot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bobot/32/21622_2.png) [@bobot](https://boards.straightdope.com/u/bobot)\ **Post date:** [March 8, 2021, 10:05pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/5 "2021-03-08T22:05:07Z")
The possibilities… If you twist an ankle and don’t feel like dealing with it, just chop at the neck and wait for your new ankles. ---
**Author:** ![blondebear](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/blondebear/32/1022_2.png) [@blondebear](https://boards.straightdope.com/u/blondebear)\ **Post date:** [March 8, 2021, 10:23pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/6 "2021-03-08T22:23:01Z")
Sort of puts a reverse twist on the old joke: Wanna lose 10 pounds of ugly fat? Cut off your head! ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [March 8, 2021, 10:36pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/7 "2021-03-08T22:36:40Z")
> [@Pleonast](#): > > But isn’t it more like chopping off its body? > [@bobot](#): > > I hope it is made explicitly clear that this does not work on people! How do you know it doesn’t work on people? I mean, plenty of people have had their heads chopped off, but when has anyone ever tried chopping off their body? ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [March 8, 2021, 10:47pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/8 "2021-03-08T22:47:32Z")
I read the whole article and did not find out the question formed on reading the headline: How does the slug effect the separation? It’s not like it can wield a tiny hatchet. Does it just will itself in two? ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [March 8, 2021, 10:57pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/9 "2021-03-08T22:57:25Z")
Basically yes. From the NY Times article on this, which I didn’t link to because it’s paywalled: > [@](#): > > Ms. Mitoh also saw signs that the sea slug’s wound was self-inflicted: It was as if the sea slug had dissolved the tissue around its neck and ripped its own head off. Self-amputation, known as autotomy, isn’t uncommon in the animal kingdom. Having the ability to jettison a body part, such as a tail, helps many animals avoid predation. However, no animal had ever been observed ditching its entire body. > > … > > For example, these sea slugs have a “breakage plane” along their necks that allows for a clean break. [Many lizards, including geckos](https://www.nytimes.com/2017/02/07/science/fish-scale-gecko.html), have a similar breakage plane near the base of their tail. Many lizards have a breakage plane on their tails where they can shed them to distract predators. ---
**Author:** ![John\_DiFool](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_difool/32/19543_2.png) [@John\_DiFool](https://boards.straightdope.com/u/John_DiFool)\ **Post date:** [March 8, 2021, 11:05pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/10 "2021-03-08T23:05:46Z")
> [@Pleonast](#): > > Fascinating, in an eldritch horror sort of way. But isn’t it more like chopping off its body? Indeed. [NSFW 2 click rule] [https://www.youtube.com/watch?v=0mELdCU1GSw](https://www.youtube.com/watch?v=0mELdCU1GSw) ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [March 9, 2021, 1:15am UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/11 "2021-03-09T01:15:14Z")
The first time I took my son to Hawaii, he was about 9 years old. He wanted to catch a gecko, and spent quite a while stalking them. He finally managed to grab one by the tail. The tail popped off and the gecko ran away, leaving my son holding the squirming tail. He screamed and dropped it, and lost any further interest in catching geckos. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [March 9, 2021, 3:33am UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/12 "2021-03-09T03:33:00Z")
> [@Pleonast](#): > > Fascinating, in an eldritch horror sort of way. > > _That is not dead which can eternal lie, > > And with strange aeons even death may die_ Stranger ---
**Author:** ![snfaulkner](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snfaulkner/32/433_2.png) [@snfaulkner](https://boards.straightdope.com/u/snfaulkner)\ **Post date:** [March 9, 2021, 4:06am UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/13 "2021-03-09T04:06:06Z")
Time to bust out the petri dishes and flamethrowers…again. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [March 9, 2021, 5:59am UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/14 "2021-03-09T05:59:37Z")
The axolotl is well known as a vertebrate that can regrow stuff - entire limbs, eyes, parts of the brain. The fact that it’s also cute is probably not a coincidence - it is neotenic, it seems to have evolved to retain what resembles a juvenile state in other salamanders. There is a lot of ongoing research into its regenerative abilities, since it may ultimately provide insight into how regrowth might be induced for injured humans. > **[Complete Axolotl Genome Could Reveal the Secret of Regenerating Tissues](https://www.smithsonianmag.com/science-nature/complete-axolotl-genome-could-reveal-secret-regenerating-tissues-180971335/)** > > The aquatic salamander's genome is one of the most complex sets of genetic instructions in the world ---
**Author:** ![robardin](https://avatars.discourse-cdn.com/v4/letter/r/43a26b/32.png) [@robardin](https://boards.straightdope.com/u/robardin)\ **Post date:** [March 9, 2021, 1:17pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/15 "2021-03-09T13:17:22Z")
More like “if a sea slug should get decapitated”. Lacking any appendages, or many handy sharp planar surfaces on the ocean floor to hurl itself against with sufficient speed or force, even if it decided to “chop off its own head” willfully, it’d have a tough time managing to do so. ---
**Author:** ![robardin](https://avatars.discourse-cdn.com/v4/letter/r/43a26b/32.png) [@robardin](https://boards.straightdope.com/u/robardin)\ **Post date:** [March 9, 2021, 1:29pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/16 "2021-03-09T13:29:51Z")
OK, now having read the article all the way to the bottom, it seems it IS something they “just do” on their own: “The self-decapitation part of the sea slugs’ process adds to the mystery though. The researchers suggest the action may be a way to get rid of internal parasites, but the impetus is unclear.” But… HOW? They have an internal head detachment feature that just drops the head off of the rest of the body to start anew? And if they got the slugs to do this under controlled circumstances (not stated in the CNET article, but typically required to publish a paper), doesn’t that mean they should have some idea as to what triggered it? ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [March 9, 2021, 1:42pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/17 "2021-03-09T13:42:26Z")
> [@robardin](#): > > And if they got the slugs to do this under controlled circumstances (not stated in the CNET article, but typically required to publish a paper), doesn’t that mean they should have some idea as to what triggered it? You can publish observational studies. You don’t need to do experiments. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [March 9, 2021, 2:11pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/18 "2021-03-09T14:11:43Z")
> [@Colibri](#): > > You don’t need to do experiments. dammit. ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [March 9, 2021, 2:20pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/19 "2021-03-09T14:20:31Z")
I had been looking for a very long time for the word _breakage plane_, thanks a lot! ([link](http://www.untrans.eu/deutsch/woerter/sollbruchstelle.html) in German) And the frog book is on its way too, thanks for that as well! 😃 ---
**Author:** ![Ike\_Witt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ike_witt/32/283_2.png) [@Ike\_Witt](https://boards.straightdope.com/u/Ike_Witt)\ **Post date:** [March 9, 2021, 2:24pm UTC](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476/20 "2021-03-09T14:24:04Z")
This information will hopefully be incorporated into some sort of horror movie. A geneticist will try to splice slug DNA into the body of the worlds most violent criminal (for reasons). It practically writes itself. [Next page](https://boards.straightdope.com/t/sea-slug-can-chop-off-its-own-head-and-then-regrow-its-body/937476.md?page=2)