7 ms·

The tail seems like vestigial anatomy (originally useful in fish) that has three possible states in mammals: 1. Repurposed for a new function (tree swinging, si

The tail seems like vestigial anatomy (originally useful in fish) that has three possible states in mammals: 1. Repurposed for a new function (tree swinging, signals) 2. Not much used but still in the repo (mice) 3. Garbage collected (apes).

ndsipa_pomu 3y ago
I'm curious about the "garbage collected" theory as there doesn't seem like a lot of selection pressure to remove tails simply due to them not being useful and consuming energy to grow. The appendix is a far more likely candidate for garbage collection as it has no obvious function and can easily cause death if it bursts. I suspect that there's another reason that apes lost their tails - most likely related to walking on two feet. Edit: According to this study (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6417348/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6417348/), the tailed chap had difficulty/pain when sitting and during other activites
- wizzwizz4 3y ago
  > The appendix is a far more likely candidate for garbage collection as it has no obvious function Preserving the gut microbiome through diarrhoea and vomiting.
  - ndsipa_pomu 3y ago
    I didn't know about that, but it seems a poor trade-off to me. Acute appendicitis is the most common abdominal surgical emergency in the world.
    - brohee 3y ago
      Yet most people never suffer it, while I'd assume 100% of the population suffered bouts of vomiting/diarrhea. Looks like the trade-off is alright.
      - mcv 3y ago
        Yeah, I suspect a lot more people have experienced diarrhea than appendicitis. If preserving gut bacteria is important enough, then the appendix clearly does have a function. But it might not be that important at all; do people with an appendectomy struggle more to recover from diarrhea?
- cout 3y ago
  In that study the tail was not innervated so there would be no way to voluntarily move the tail out of the way when sitting.
dTal 3y ago
Tails are extremely useful to mice, especially for balance and climbing: https://www.theguardian.com/lifeandstyle/2019/apr/30/why--mice-such-long-tails-notes-and-queries#comment-128531286 https://www.theguardian.com/lifeandstyle/2019/apr/30/why--mi... Be careful with assuming functionlessness, in general. Evolution does not like spending energy on sticky-out bits that are prone to injury, or good handles for predators to catch, unless they provide some serious advantage.
nightfly 3y ago
Also used to distract and confuse (deer and rabbits)
rikroots 3y ago
Kangaroos use their tails as a fifth leg - https://phys.org/news/2014-07-tale-kangaroo-tail.html https://phys.org/news/2014-07-tale-kangaroo-tail.html
mcv 3y ago
#1 covers a whole range of different possible functions, of course. Balance and navigation (birds, cats, etc) is still somewhat related to the original function in fish. Sexual attraction/signalling Grabbing stuff A third leg in kangaroos Fly swatter (cows and other large grazers) For kids to hold onto their parent (elephants) I'm sure there's a lot of other creative applications of tails that I'm missing.

ndsipa_pomu 3y ago

I'm curious about the "garbage collected" theory as there doesn't seem like a lot of selection pressure to remove tails simply due to them not being useful and consuming energy to grow. The appendix is a far more likely candidate for garbage collection as it has no obvious function and can easily cause death if it bursts. I suspect that there's another reason that apes lost their tails - most likely related to walking on two feet. Edit: According to this study (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6417348/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6417348/), the tailed chap had difficulty/pain when sitting and during other activites

wizzwizz4 3y ago
> The appendix is a far more likely candidate for garbage collection as it has no obvious function Preserving the gut microbiome through diarrhoea and vomiting.
- ndsipa_pomu 3y ago
  I didn't know about that, but it seems a poor trade-off to me. Acute appendicitis is the most common abdominal surgical emergency in the world.
  - brohee 3y ago
    Yet most people never suffer it, while I'd assume 100% of the population suffered bouts of vomiting/diarrhea. Looks like the trade-off is alright.
    - mcv 3y ago
      Yeah, I suspect a lot more people have experienced diarrhea than appendicitis. If preserving gut bacteria is important enough, then the appendix clearly does have a function. But it might not be that important at all; do people with an appendectomy struggle more to recover from diarrhea?
cout 3y ago
In that study the tail was not innervated so there would be no way to voluntarily move the tail out of the way when sitting.

dTal 3y ago

Tails are extremely useful to mice, especially for balance and climbing: https://www.theguardian.com/lifeandstyle/2019/apr/30/why--mice-such-long-tails-notes-and-queries#comment-128531286 https://www.theguardian.com/lifeandstyle/2019/apr/30/why--mi... Be careful with assuming functionlessness, in general. Evolution does not like spending energy on sticky-out bits that are prone to injury, or good handles for predators to catch, unless they provide some serious advantage.

nightfly 3y ago

Also used to distract and confuse (deer and rabbits)

rikroots 3y ago

Kangaroos use their tails as a fifth leg - https://phys.org/news/2014-07-tale-kangaroo-tail.html https://phys.org/news/2014-07-tale-kangaroo-tail.html

mcv 3y ago

#1 covers a whole range of different possible functions, of course. Balance and navigation (birds, cats, etc) is still somewhat related to the original function in fish. Sexual attraction/signalling Grabbing stuff A third leg in kangaroos Fly swatter (cows and other large grazers) For kids to hold onto their parent (elephants) I'm sure there's a lot of other creative applications of tails that I'm missing.