Under *nix, ctime is not creation time, but actually the last time the inode for the file was changed (from man stat - Last file status change time). MTime is the last modification time. As was said by kennethk in Re: File test to see creation time rather than last modified time, *nix does not record creation time of a document. An inode may change at some unexpected times (for example, when the mtime is changed).
ls also lists the -c option as
Use time of last modification of the inode (file created, mode changed, etc.) for sorting (-t) or printing (-l (ell))
I have seen the c in ctime being misunderstood for the 15-20 years I have been using *nix. In my tenure, this misunderstanding has been the cause of many mistakes on interpreting data from the filesystem.