Marauder's Map: Selective Against Marauders?

[Mandy]

No: HPFGUIDX 103909

> Pandrea
> Do we know that the Map can see through an animagi disguise?  I 
have always thought that in rat form, Peter showed up on the map AS 
> Wormtail, therefore neither Harry nor the twins ever noticed 
anything funny.  The time that Lupin noticed "Peter" on the Map, he 
had for some reason - perhaps to get away from Crookshanks - had to 
> temporarily transform back into human form, just for a minute - 
> unluckily for him, the very minute Lupin happened to be looking at 
> the Map.  I'm not sure if this theory really holds, though, is 
there anything to contradict it?
 

Mandy here: 
The Map shows the birth name of the person it's displaying not their 
nickname.  

Wormtail, Moony, Padfoot and Prong are simply nicknames. Used by the 
boys themselves.  LV had addopted the name of Wormtail for Peter 
because he dispises Peter for living as a rat and refuses to refer to 
Peter by his full name. 

Whether Peter is in animagus form or not, he would still show up as 
Peter Pettigrew on the map.