Sirius, Peter and James managed to become Animagi at a very young age (somewhere in their teens). So when young Sirius transformed into his animal form, was it the form of an adult dog, or an adolescent dog? (I am sure fan-art of puppy Sirius exists, but I do not want to stain my computer).

Furthermore, McGonagall was really old. Her cat form in the movie did not look too old, but we only see that form for two short scenes and the movies can be misleading. When McGonagall transforms, does she turn into an adult cat, or would her cat form look more like Mrs. Norris? (Perhaps McGonagall and Mrs. Norris could form a duo called "The Senile Felines")

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    Near-adult adolescent mammals like the marauders would have been are very near the size of the grown up animal. Judging the age of an animal by sight is a pretty hard thing. Jul 18, 2017 at 17:40

2 Answers 2


We don't have any explicit info on whether an Animagus' animal form reflects the age of the Witch or Wizard.

However, we do know that an Animagus' animal form does not age in the usual way the animal they are imitating does, since Pettigrew stayed as a rat for 12 years, despite most rats only living for 1 or 2.

We also know that an Animagus will have distinguishing marks, such as McGonagall and Rita Skeeter's glasses, and that a major physical change, such as loss of a finger or gaining of a metal arm (Pettigrew again), is reflected in the animal form.

I would personally regard growing old / gaining wrinkles as a fairly major physical change, so naturally these would also become reflected in the animal form.

So, given the above, I think it is reasonable to assume that an Animagus' animal form does indeed reflect the age of the Witch or Wizard, though as I said, there is no explicit, canon information confirming as such.

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    Well, I would say that the fact that Peter managed to survive as a rat for 12 years supports the assertion that the animal for reflects the age of the wizard. Since animals and humans have different life spans, then an Animagus that spends an extended period of time in animal form would either prematurely die of old age or remain at the relative maturity level of their natural form's age. Jul 18, 2017 at 9:41
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    Just surviving for 12 years could also mean that the animal forms don't have an age, and always look the same, as a Patronus does when it is cast (note that McGonagall's patronus and animagus forms are both a cat). My argument hinges more on the fact that the animal form reflects physical changes and characteristics of the human form, meaning that the animal form can change appearance. Jul 18, 2017 at 9:47
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    The immediate physical state is also taken into account, on Chapter 1 of the first novel, Mc Gonagall is implying that after sitting on a wall, she felt stiff as a cat and still felt stiff after transforming too. Jul 18, 2017 at 19:02
  • That is an excellent addition @LudovicZenohateLagouardette . That certainly makes the claim that age is reflected more credible. Jul 18, 2017 at 19:13
  • The statement about most rats living only 1 or 2 years assumes that if there's any syncing of human and animal lifespan, it's absolute. It may very well be more like a percentage. Eg, middle aged human = middle aged animal, young human = young animal, etc.
    – Kat
    Jul 19, 2017 at 20:10

Animals in The Wizarding World are much different from those of the "Muggle world"; pure speculation based on canon evidence give to us, but it seems reasonable to say that:

An Animagus' age isn't reflected in their animal form.

Consider this: James, Sirius and Peter were all around 15-16 when they first become Animagi.

[Remus] “Peter needed all the help he could get from James and Sirius. Finally, in our fifth year, they managed it. They could each turn into a different animal at will.”

At that age, you'd be considered an "adolescent". Realistically their Animagi forms would be of "adolescent" age as well. However, this isn't the case. Peter turns into a rat, too small for comparison. James and Sirius turn into a stag and a (rather large) dog, respectively. It's said (by Lupin himself) that 2 large animals were able to control Lupin in his fully-grown werewolf form.

[Remus] “Soon we were leaving the Shrieking Shack and roaming the school grounds and the village by night. Sirius and James transformed into such large animals, they were able to keep a werewolf in check.”

[Remus] “Well, of course, Snape tried it if he’d got as far as this house, he’d have met a fully grown werewolf but your father, who’d heard what Sirius had done, went after Snape and pulled him back, at great risk to his life, Snape glimpsed me, though, at the end of the tunnel.”

Or, more specifically: into such large animals. In other words, they changed into adult animals. I certainly don't see how an adolescent dog, or stag, could be considered as (such) large animals.

To reinforce this...

[Sirius] “And there was Peter, on the front page . . . on this boy’s shoulder. . . . I knew him at once . . . how many times had I seen him transform? And the caption said the boy would be going back to Hogwarts . . . to where Harry was. . . .”

Sirius hadn't seen Peter for 12 years since the incident1. If he was able to recognise Peter's rat form at age 15, to recognise him again so many years later would mean that Peter's rat form didn't technically "age", even though Peter himself did. Of course, this may all be referring to Peter's toe, but Sirius does recount the multiple times he had seen Peter transform, prior to the incident.

1 Peter "blowing himself up".

“Just before he transformed,” said Black. “When I cornered him, he yelled for the whole street to hear that I’d betrayed Lily and James. Then, before I could curse him, he blew apart the street with the wand behind his back, killed everyone within twenty feet of himself — and sped down into the sewer with the other rats. . . .”

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    @DisturbedNeo he only saw Peter (in rat form) without a toe once, during the incident I quoted above. Sirius rhetorically states: "how many times had I seen him transform?" which would refer to the incidences at school where they'd transform to animals together.
    – Voronwé
    Jul 18, 2017 at 9:42
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    The rat could have had familiar colouring or markings. As for James and Sirius being able to handle werewolf Lupin, remember that Lupin was a teenager as well. They would only have to handle a teen wolf and not an adult werewolf, so they did not have to be fully grown to handle him. Also, many large breeds of dogs grow very rapidly. Rhodesian Ridgebacks and Boerbulls are prime examples of that. Jul 18, 2017 at 9:46
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    @MagikarpMaster ahem. Fully grown werewolf -- will add a quote in my answer.
    – Voronwé
    Jul 18, 2017 at 9:47
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    Fair enough @Voronwë. But do bear in mind that even when accounting for proportional differences in life-span, animals usually have a shorter period of adolescence than humans. 16 for humans is where the vast majority of physical growth slows down or even stops for most human males, and considering how much shorter the relative period of adolescence is for animals, the fact that James and Sirius's animal forms were fully grown is not a definitive indication that age is not reflected. That being said, your answer is very convincing. Jul 18, 2017 at 9:55
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    That is true. Can't say for Stags, but if you convert "human" years to "dog" years, a 15 year old human is roughly a 2 year old dog, which will almost certainly be fully grown. Jul 18, 2017 at 12:16

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