"If you made a better rat than a human, it's not much to boast about, Peter."
     -- Sirius Black

"Your devotion is nothing more than cowardice. You would not be here if you had anywhere else to go."
     -- Lord Voldemort

Peter Pettigrew was born c. 1960. He entered Hogwarts at the same time as Sirius Black, James Potter, and Remus Lupin. Peter did not have the same level of skill that the others had but he idolized the others in that group. Madam Rosmerta of the Three Broomsticks referred to Peter as "that fat little boy who who was always tagging after them at Hogwarts." (PA10) They included him and helped him. It was under their tutelage that he learned to become an Animagus. Peter learned to turn himself into a rat and used the nickname "Wormtail." We do not know which house Peter was sorted into. It seems likely that he and the rest of that group of friends was in Gryffindor, but we just don't know.

Peter was a person who is easily influenced by those around him, allying himself with whomever is the strongest. Lupin, Sirius, and Potter were the leaders in their year so he naturally followed them. But these were the years of Voldemort's power, and the Potters were for some reason particularly sought after by him. Once out of school, Pettigrew was an easy target for the Dark Lord. He was coerced into becoming a spy for Voldemort. As he put it, 

"Sirius, Sirius, what could I have done? The Dark Lord... you have no idea...he has weapons you can't imagine...I was scared, Sirius, I was never brave like you and Remus and James. I never meant it to happen...He-Who-Must-Not-Be-Named forced me...He--he was taking over everywhere! Wh--what was there to be gained by refusing him? You don't understand! He would have killed me, Sirius!" (PA19)

"Scabbers" 
November 1981 - June 1994
Peter had actually transformed into a rat and escaped into the sewers. He was in a precarious position now, since Voldemort was no longer around. The other followers of Voldemort, who knew that their Lord had gone to attack the Potters on Peter's advice, were bent on revenge against him. He stayed in the form of a rat to hide, while the Wizarding World assumed he was a dead hero.

Somehow he allowed himself to become the property of Percy Weasley. He became "Scabbers," the pet rat. In this way, he was able to keep tabs on the Wizarding World. He always kept an ear open for news of Voldemort's whereabouts. Eventually, he was passed on to Ron Weasley and spent several years as Ron's pet, even living at Hogwarts in the same dorm room as Harry Potter, the enemy of his master. But he did nothing, waiting for some sign that Voldemort was rising again.

Ron was very fond of Scabbers, even though he didn't seem to be worth much as a pet. He tended to sleep a lot and do little else. Once, however, when Harry and Ron were in a confrontation with Malfoy, Crabbe, and Goyle, Scabbers woke up long enought to bite Goyle's knuckle. Fred later called this "his finest hour."

Scabbers was not fond of Hermione's cat, Crookshanks, and with good reason. Crookshanks is part Kneazle, which means that he can sense duplicity. He saw right through Peter's disguise and tried to attack him whenever he got a chance. 

Discovery and Flight
Peter lived for years as a pet rat. He even accompanied his master, Ron, on a family trip to Egypt in August of 1993. The family's picture appeared in the Daily Prophet while they were on the trip and Scabbers was visible on the picture. Sirius Black, imprisoned in Azkaban, happened to ask Cornelius Fudge for a copy of the paper and spotted the rat. He recognized his old "friend" at once and resolved to escape from the Wizard's Prison and track the traitor down. The pursuit eventually led Sirius and Pettigrew, along with Remus Lupin, Harry, Ron, Hermione, and Severus Snape, to a showdown in the Shrieking Shack. Scabbers' true identity was revealed and Sirius and Lupin stood ready to execute him. Harry intervened, however, and asked that Peter be allowed to live. Pettigrew therefore owes Harry a life debt, which  may or may not prove important in the future.

By unlucky chance, Pettigrew escaped that night. He transformed back into a rat and went searching desperately for his old master, Voldermort. He traveled to Albania in rat form. He talked to the rats and other animals he met along the way and discovered that there was some dark, non-corporeal being lurking in the forests of Albania. Peter traveled there to find Voldemort. Along the way, in a wayside inn, Pettigrew met Bertha Jorkins, who was on holiday. He lured her into the forest with him and she fell into the clutches of the Dark Lord.

The Servant of Lord Voldemort
Pettigrew proved to be the helper Voldemort needed to begin his return to his body. Peter, with Voldemort's instructions, created the potions his master needed to gain a temporary body. Pettigrew milked the venom from Nagini, a huge snake, which was used as part of the potion. He carried Voldemort's weak, small body on the long journey back to Britain, where they took up temporary residence in the Riddle House outside of Little Hangleton. Voldemort called Peter "Wormtail." 

When Harry Potter was captured, it was Peter who killed Cedric Diggory, who bound Harry, who set up the cauldron over the fire, and who cut Harry's arm for blood for the potion. Peter then cut off his own right hand to add to the potion. From that horrible mixture, the Dark Lord was reborn in his old body. He cast a spell which created a new shining and powerful hand for Pettigrew. 

Peter Pettigrew
AKA: Wormtail, Scabbers
eyes: small, watery
hair: thin, colorless, unkempt with a bald patch
build: small, not much taller than Harry or Hermione
distinguishing features: rat-like face, missing finger on his right hand; after this hand was cut off, it was replaced by a magical shining silver hand by Voldemort
complexion: pasty