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

[potioncat]

No: HPFGUIDX 182623

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.

> 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.

Some of us theorized that his Patronus might change to something that 
would show his loyalty after killing DD. But that doesn't seem to be 
what happened. We never knew what it was anyway. What had been 
expected was that he would send a message to the Order or to Harry 
and no one would know it was from him. Well, actually, that did 
happen. Just not quite the way we expected.