Board Thread:Off Topic/@comment-25396609-20160923220030/@comment-25396609-20160925230256

Going to take ma a while to track down some articles or papers on the phenomena; but the gist of it is that all humans have a tail during extremely early developmental phases (5 weeks or so) which is usually absorbed by 8 weeks. in some (incredibly rare) cases the tail is never absorbed and continues to grow, resulting in a very small tail.

Best I can source find is the abstract for a paper on the subject, may be able to track something down if i have a bit more time.

http://thejns.org/doi/abs/10.3171/jns.1985.63.3.0461?journalCode=jns

I know scorpion tails use muscles, but i can't recall the specifics right now. they are structured very differently though, as the skeleton is around the muscle rather than the muscle being around the skeleton. mechanical differences which i will need more time to find diagrams and such for.