Was Voldemort an Animagus? No, Voldemort was not an Animagus. He didn't see any reason to become an Animagus despite being a gifted wizard and knowing a lot of magic. This may simply be because his sole purpose was to obtain immortality and become the strongest wizard who could control the world around him.
With Sirius and James' help, Pettigrew becomes an Animagus, with the ability to transform at will into a rat. After leaving Hogwarts, Pettigrew joins forces with Voldemort, and in exchange for his own life becomes Voldemort's spy within the Order of the Phoenix, of which Pettigrew is a member.
Being an animagus wasn't Dark magic, nor particularly useful for ruling over everyone, nor for genocide, nor for achieving immortality, nor for infamy, so Voldy never bothered to become an animagus.
As a pack animal, or as a “lone wolf,” the wolf is a perfect fit for Harry's Animagus form.
Transfiguration and Animagi are different
For example: if Viktor Krum can transfigure his head into a shark's, like he does in Goblet of Fire, that doesn't mean he is an Animagus. Transfiguration is a form of spell-casting, whereas becoming an Animagus is forever. And yes, he could turn into a falcon. Lucky.
And there is no question that Snape was a talented wizard, and that he could have become one if he had wanted to. But the fact is, there is not one single shred of evidence in Canon that Snape ever became an animagus.
Following both ordeals, Ginny grew into a confident young woman. Her and her friends followed in the footsteps of a previous generation, completely unbeknownst to them, and became Animagi at the age of fourteen, to support their best friend, Maisie Cattermole. Ginny took the form of a grey mare.
Pettigrew's Animagus form was a rat, from which his nickname "Wormtail" was derived. The four friends called themselves the Marauders and designed a map to navigate Hogwarts.
Animagus. Lily's animagus form is a Doe, coupling with her husband, James Potter who is a Stag. Severus Snape's animagus is also a Doe.
In the Harry Potter books, only a few Animagi (registered and unregistered alike) are even mentioned. They are James Potter, Sirius, Wormtail, Skeeter, McGonagall, Talbott Winger, and an unnamed witch who can turn into a cat. The fact that there are so few Animagi just causes us fans to want to know more about them.
In the films, Hermione's Patronus is depicted as a European River Otter, and her Animagus form would most likely be the same animal, as confirmed by author J.K. Rowling.
Usually people turn into Animagi who match their Patronus, so it is safe to assume Snape would be a doe. But based on his morals qualities, I'd say maybe some kind of prey bird; a crow would be the perfect match.
Albus Dumbledore indirectly stated that the Marauders never revealed to anyone, the Order of the Phoenix included, that three of them became Animagi until mid-1994, when Sirius Black told the entire story to him.
But what kind of beast though? An Animagus is still a witch or wizard, and Aurors can fight werewolves like Fenrir Greyback, so it's very unlikely Grindelwald is either of those. If only Rowling had just introduced us to a totally different way for a human to turn into a deadly creature…
Draco is not an animagus in the story. However, if he were to become one, I believe he would be a Siamese cat. His belief in his superiority and his snobbish manner line up with Siamese traits, but he, like the cats, loves his family deeply.
Sirius Black and James Potter attended Hogwarts together, and Sirius is Harry's godfather. Sirius is an Animagus, which means he can transform himself into a black, shaggy dog named Padfoot at will.
Falco Aesalon — Falcon; the first recorded Animagus; the registration system was not in existence in his time.
Both Lupin and Tonks die in combat, killed by Dolohov and Bellatrix Lestrange, respectively, leaving Teddy an orphan with Harry Potter as his godfather and Andromeda Tonks as his guardian.
Extremely intelligent, exceedingly talented and a "wicked" Animagus, it's no wonder Minerva McGonagall is Head of Gryffindor house.
It's a long, complicated process. Harry had reason to work on his DADA skills to stay alive, so for extracurricular work that took precedence.
Otter (Hermione Granger)
Her Patronus, the otter, is a clever and dexterous animal; some have even been known to juggle small rocks. Otters have also featured in many classics of English literature such as Tarka the Otter, Ring of Bright Water and The Wind in the Willows.
James Potter
James's Animagus form was that of a stag, which earned him his nickname, Prongs.
He is seen in his animagus form by Lucius Malfoy while on Platform 9 3/4. Lucius, as a Death Eater, knows about Sirius' animagus form because Peter Pettigrew told the Death Eaters when he returned to their side after book 3.
Because he didn't need to. For him, he was already facing one issue that was enough for a lifetime. He did not have the need to become an animagus like James, Sirius, Peter or Rita Skeeter. The other Marauders became Animagi in order to help their friend during his involuntary transition to being a werewolf.