Snape's Messenger Patronus (was Re: Snape's Dementor lesson)

[Carol]

No: HPFGUIDX 182632

Jayne: 
> > The explanation that Carol gave above is great and very plausable. 
> > Sorry I snipped it so much.
> 
> Potioncat:
> Yes it is. The fact that others wouldn't instantly recognise its 
significance hadn't occured to me, and might work. I'm still mulling
it over.

Carol responds:

Thanks, both of you.
> 
> > Jayne:
> >  Snape ,it has been mentiond before had changed his patronus. Do
we know when and what it was before.?
> 
> Potioncat:
> Erm. I don't think there's any canon for that. We have been told by
JKR in an interview that the Expecto Patronum spell is not taught at 
Hogwarts. Of course, maybe it was in the Marauders' days. But, the 
point is, Snape's Patronus may have always been a doe. In fact, that's
what I think. <snip>

Carol responds:

And yet JKR goes to some effort, via Tonks, to show that a Patronus
can change. Snape sees and correctly interprets Tonks's changed
Patronus (we don't know what it was before because it isn't relevant),
and Harry, trying to figure out what's wrong with Tonks and
remembering Snape's words, asks Lupin, "the man who knew all about
Patronuses," why a Patronus would change. Lupin, of course, knows
perfectly well why *Tonks's* Patronus has changed and what it would
change into, but doesn't want to tell that to Harry (who apparently
thinks it might be Sirius's Animagus form but doesn't get to test his
theory because they're interrupted by Percy and Scrimgeour. JKR does
that a lot . . . .). Instead, Lupin is silent for a moment, taking his
time to swallow his food (and formulate a response that answers the
question without giving away anything personal), "Sometimes . . . a
great shock . . . an emotional upheaval . . . ." (HBP Am. ed. 340).

While this response seems, in context, to explain the change in
Tonks's Patronus (which is really the result of unrequited love or
Lupin's unwillingness to allow himself to love and has nothing to do
with blaming herself for Sirius's death, as Hermione has theorized
with regard to Tonks's loss of her Metamorphmagus abilities), it
really fits better with what happened to young Severus Snape. His own
involvement in the eavesdropping, followed by Lily's death, which he
had tried and failed to prevent and for which he still blamed himself,
would certainly qualify as "a great shock" and "an emotional
upheaval." IMO, JKR is preparing the reader, through Tonks, for
Snape's changed Patronus.

And yet, I agree with Potioncat that logically, Snape's Patronus
should always have been Lily in some form. Maybe it was originally
something else that represented her (a uniconr, which symbolizes
purity?) but became Lily's own Patronus on her death. Yes, the
Patronus Charm is not taught at Hogwarts, and yes, Snape seems to have
some other method (I think it's Occlumency, as I said recently in a
post that I can't find, the site's search engine having failed me) for
protecting himself against Dementors (probably the same method that
Fudge uses when he communicates with them), but I think that Severus
Snape, being both gifted and powerful, would have taught himself to
cast a Patronus long before Dumbledore taught the Order how to use
them to communicate. In short, I think he had a Lily-related Patronus
that reflected his love for her that changed to a doe, Lily's own
Patronus, after Godric's Hollow. 

And yet, there's that remark to Dumbledore after he casts the doe
Patronus to show his love for Lily when DD remarks, "After all this
time?" and Snape responds, "Always." But I think that DD simply meant
"You still love Lily?" and Snape means that he'll always love her.
It's quite possible that Dumbledore has seen that Patronus before and
has never realized its significance. And now, his eyes full of tears,
he does.

As for two people having the same Patronus, I think that Patronuses
are like wands, which can be made of the same wood and have the same
kind of core and yet still be different, just as each unicorn and
dragon (and Phoenix, if there's more than one at a time) is different.
Each animagus form is also undoubtedly different, as well. Another
person with a dog Animagus probably wouldn't resemble Sirius Black's
big black shaggy dog, and another person's dog Patronus probably
wouldn't resemble Ron's Jack Russell terrier.

BTW, we do see two people with the same animal as a Patronus: Minerva
McGonagall, the cat Animagus, and Dolores Umbridge, who has all those
horrible kitten plates decorating her office, both have a cat as their
Patronus. And, given the association in folklore between cats and
witches, I would bet that a lot of Witches (and perhaps some Wizards
as well) have cat Patronuses. If Figgy or Filch could cast a Patronus,
which, of course, they can't, being Squibs, I'm pretty sure that
theirs would be a cat as well. (Filch's would no doubt be Mrs. Norris
and Mrs. Figg's would perhaps resemble Mr. Tibbles.)

Carol, still just speculating based on the little canon available on
the topic