Why didn't the Marauder's Map show Mad Eye Moody hidden in the trunk?

Question

I found this question in the comments of another question, but never found it posted separately here on SF&F-SO. So, I am posting it here out of curiosity.

"Did the Marauder's Map show Mad Eye Moody when he was hidden inside his own trunk?"

The map should show Mad-Eye Moody inside the DADA teacher's office even when Barty Crouch Jr was impersonating Moody elsewhere. One glance at the map would be enough to blow Barty Jr's cover.

Was there something about the magical chest that Barty hid him in? One possible answer given in the other post is "The inside of Moody's trunk might be unplottable," The trunk has the Undetectable Extension Charm to make the inside bigger than the outside (much like the Weasley's tent or Hermione's purse), but nothing in the description for that spell says it automatically makes the interior unplottable.

Is there anything from the books that hints at why he didn't show up on the map?

Answer 1

Because the Map doesn't show people hidden inside magical objects/rooms.

I don't think that Moody would have appeared on the Map. So I agree with the premise of the question - although I think that it has just as much to do with the Map as the trunk. What matters is what the Map can see and what the Map can't see.

We know that the Marauder's Map doesn't show everywhere in Hogwarts. One of the hidden passageways in Hogwarts isn't on it, for instance.

“How long’s this been here?” Ron asked as they set off. “It isn’t on the Marauder’s Map, is it, Harry? I thought there were only seven passages in and out of school?”
_{(Deathly Hallows, Chapter 29, The Lost Diadem).}

The Map also misses off locations which are hidden by magic. Presumably, the Chamber of Secrets wasn't on it. I can hardly imagine Fred and George not noticing an entire hidden chamber in the depths of Hogwarts or failing to report its existence when people were being attacked left, right and centre during Harry's second year.

We know that the Map can penetrate Invisibility Cloaks and magical disguises.

“The point is, even if you’re wearing an Invisibility Cloak, you still show up on the Marauder’s Map."
_{(Prisoner of Azkaban, Chapter 17, Cat, Rat and Dog).}

However, it can apparently be duped by a magical location like the Room of Requirement. The Map doesn't show the Room of Requirement as the Room's magic is powerful enough to hide the Room from the Map.

“I think it’ll be part of the magic of the room,” said Hermione. “If you need it to be Unplottable, it will be.”
_{(Half-Blood Prince, Chapter 21, The Unknowable Room).}

Harry discovers this when he looks for Malfoy on the Map when he's in the Room of Requirement and cannot find him. Not only does the Room not appear on the Map but Malfoy himself doesn't appear on the Map.

Although he consulted the map as often as he could, sometimes making unnecessary visits to the bathroom between lessons to search it, he did not once see Malfoy anywhere suspicious...at these times Malfoy was not only nowhere near them, but impossible to locate on the map at all.
_{(Half-Blood Prince, Chapter 18, Birthday Surprises).}

And still there were those inexplicable times when Malfoy simply vanished from the map...
_{(Half-Blood Prince, Chapter 19, Elf Tails).}

I think it's important that the Map doesn't have a glitch when it can't detect a person; it doesn't show Malfoy hovering at the entrance to the Room of Requirement where it last saw him. He simply doesn't appear on the Map at all.

Now the Room of Requirement is hardly unique in hiding its users from outsiders. The Pensieve works similarly; to all intents and purposes a person inside the Pensieve doesn't exist in the material world as they are hidden inside a magical item. Montague was in a similar position when he was trapped in between the two Vanishing Cabinets (when I believe he was in a netherworld outside of time and space). We don't have canon proof either way but I suspect that people in Pensieve or trapped in Vanishing Cabinets don't appear on the Map either.

Moody's situation is similar to the examples above. He was in a magical object that hid him from the outside world. He was in a particular physical space (the trunk), yet simultaneously absent. His underground dungeon was only visible when a particular key was turned in the seventh key-hole in the trunk. The trunk contains multiple realities, multiple spaces which co-exist simultaneously. I think that, as far as the Map was concerned, anyone existing in any of those spaces within the trunk was hidden. So Moody wouldn't have appeared on the Map.

The trunk - like the Room of Requirement, the Penseive or the Vanishing Cabinets - was a magically enhanced space that rendered individuals within it invisible to the Marauder's Map.

---

The Map was dangerous for Crouch anyway, though.

As a supplementary point, just because Moody didn't show up on the Map didn't mean that it couldn't have blown Crouch's cover. Crouch himself recognised the danger of the Map.

"I used the map I had taken from Harry Potter. The map that had almost ruined everything.”
_{(Goblet of Fire, Chapter 35, Veritaserum).}

Harry wouldn't have needed to have seen Moody trapped in his study. He would only have needed to look at the dot labelled 'Barty Crouch' and realise that the person standing next to him wasn't actually Moody. Anyone who looked closely at the Map would recognise the presence of an imposter. Crouch realised that the Map would blow his cover if discovered and so 'borrowed' it from Harry the moment he came to know about it.

Answer 2

It is unknown whether Mad Eye Moody was visible on the map even when he was hidden in his trunk. Still if he was it is completely plausible that Harry just ignored seeing him since the trunk was in the DADA teacher's room, where Mad Eye was expected to be.

In more detail:

First of all Harry does not look at the map all the time. He used the map more often during his sixth year but before that he only checked on it when he wanted to have a clear path during the night.

Even if Harry took a look at the map and saw Mad Eye Moody, so what? He wasn't on a place where one would not expect to find him. Exactly the opposite - he was in his room.

He could have seen BOTH Barty Crouch Jr. and Mad Eye in the room but this is also not something unexpected or too unusual. The map only shows "Barty Crouch" and Harry could assume that Barty Crouch Sr. is just visiting Moody for some reason.

It would have been suspicious to see Mad Eye in his room under following circumstances:

• in class when Harry sees fake Mad Eye in front of him
• during eating times in the Great Hall when fake Mad Eye is there

Still this never happens. The DADA lessons are interesting enough to keep Harry from looking at the map and the Great Hall is too crowded and Harry keeps the map a secret so he does not want to show it to everyone.

Answer 3

The Marauder's map cannot be tricked by Animagus nor by Poly Juice Portion. It displayed names in "FirstName LastName" format.

It Identified Peter Pettigrew.

“I couldn’t believe my eyes,” said Lupin, still pacing, and ignoring Harry’s interruption. “I thought the map must be malfunctioning. How could he be with you?”

“No one was with us!” said Harry.

“And then I saw another dot, moving fast toward you, labeled Sirius Black... I saw him collide with you; I watched as he pulled two of you into the Whomping Willow —”

“One of us!” Ron said angrily.

“No, Ron,” said Lupin. “Two of you.”

“What?” Ron said again, holding Scabbers close to him, looking scared. “What’s my rat got to do with anything?”

“That’s not a rat,” croaked Sirius Black suddenly.

“What d’you mean — of course he’s a rat —”

“No, he’s not,” said Lupin quietly. “He’s a wizard.”

“An Animagus,” said Black, “by the name of Peter Pettigrew.”

_{^{Harry Potter and the Prisoner of Azkaban, Chapter 17, Cat, Rat, and Dog}}

It Identified Barty Crouch Jr.

Peeves was not the only thing that was moving. A single dot was flitting around a room in the bottom left-hand corner - Snapes office. But the dot wasn’t labeled “Severus Snape”... it was Bartemius Crouch. Harry stared at the dot. Mr. Crouch was supposed to be too ill to go to work or to come to the Yule Ball - so what was he doing, sneaking into Hogwarts at one o’clock in the morning? Harry watched closely as the dot moved around and around the room, pausing here and there...

_{^{Harry Potter and the Goblet of Fire, Chapter 25, The Egg and the Eye}}

The Marauder's Map would have shown Mad Eye Moody in his room, as long as he was kept there. While all the ill doing of Bartemius Crouch Jr. would be blamed on his father.

Secondly Harry did not use the Map to spy on teachers, he basically checked it to see if the corridors were free or not.

Answer 4

Moody was not shown because the map knows the viewer's intention and only shows things of significance.

Although my answer is nearly a duplicate of my answer on Peter Pettigrew, since this is a different question, I'm posting it twice:

We clearly see that the Map DOES NOT SHOW ALL PEOPLE AT ONCE from the following quotes:

“Ron, I don’t believe it — it’s Scabbers!” Ron gaped at her. “What are you talking about?” Hermione carried the milk jug over to the table and turned it upside down. With a frantic squeak, and much scrambling to get back inside, Scabbers the rat came sliding out onto the table. “Scabbers!” said Ron blankly. “Scabbers, what are you doing here?”

And then here:

“The number of times I saw James disappearing under it…” said Lupin, waving an impatient hand again. “The point is, even if you’re wearing an Invisibility Cloak, you still show up on the Marauder’s Map. I watched you cross the grounds and enter Hagrid’s hut. Twenty minutes later, you left Hagrid, and set off back toward the castle. But you were now accompanied by somebody else.”

Now, if Scabbers was hiding in Hagrid's hut, he should have always been visible! So why did Lupin not see him in Hagrid's hut the whole time? There's simply no way to answer there were too many dots, clearly, the only dots in Hagrid's hut at the time were Hagrid's and Pettigrew's!

We also see that the viewer isn't normally on the map:

What did he have to do? He pulled out the map again and saw to his astonishment, that a new ink figure had appeared upon it, labeled ‘Harry Potter’.

This clearly implies that Harry himself had not been on the map before! (Although here the figure is new, the label itself shouldn't have been that astonishing to him.)

However there are three facts about the map that can answer the question: One, the map was invented for a specific purpose: Mischief:

Messrs. Moony, Wormtail, Padfoot, and Prongs Purveyors of Aids to Magical Mischief-Makers are proud to present THE MARAUDER’S MAP.

Also:

He took out his wand, touched the parchment lightly, and said, “I solemnly swear that I am up to no good.”

Also

“I’m getting there, Sirius, I’m getting there… well, highly exciting possibilities were open to us now that we could all transform. 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. I doubt whether any Hogwarts students ever found out more about the Hogwarts grounds and Hogsmeade than we did… And that’s how we came to write the Marauder’s Map, and sign it with our nicknames. Sirius is Padfoot. Peter is Wormtail. James was Prongs.”

These quotes show us that the map was intended for mischief, and specifically, was invented for James and Co. to be able to sneak around camp grounds.

The second fact that can answer this question is that the map is intelligent.

But even as he stood there, flooded with excitement, something Harry had once heard Mr. Weasley say came floating out of his memory. Never trust anything that can think for itself, if you can’t see where it keeps its brain. This map was one of those dangerous magical objects Mr. Weasley had been warning against… Aids for Magical Mischief Makers…

And by the episode of Snape we see further evidence of the map's intelligence:

“Professor Severus Snape, master of this school, commands you to yield the information you conceal!” Snape said, hitting the map with his wand. As though an invisible hand were writing upon it, words appeared on the smooth surface of the map. “Mooney presents his compliments to Professor Snape, and begs him to keep his abnormally large nose out of other people’s business.”

The third fact is that the map can change its appearance to help with the mischief:

What did he have to do? He pulled out the map again and saw to his astonishment, that a new ink figure had appeared upon it, labeled ‘Harry Potter’. This figure was standing exactly where the real Harry was standing, about halfway down the third-floor corridor. Harry watched carefully. His little Ink self appeared to be tapping the witch with his minute wand. Harry quickly took out his real wand and tapped the statue. Nothing happened. He looked back at the map. The tiniest speech bubble had appeared next to his figure. The word inside said, ‘Dissendium.’

This is incredible! The map not only deviated from its purpose (showing Hogwarts) it realized that Harry did not understand how to open the secret passage, so first it showed him the wand-tap, but Harry still didn't get it, so the second time Harry looked, it showed him the spell! So this map can realize the viewer's intention and difficulties!

So we know 4 facts from the books: 1)Not every dot appears on the map. 2)The map is intended for mischief. 3)The map is intelligent. 4)Using its intelligence, the map can change its appearance to help with the mischief.

From these four facts we can deduce that the map does not show everybody at once, but rather shows only people who the viewer is specifically looking for or that the map feels can interfere with the viewer's intended mischief (or the whatever the viewers intention is) with the map.

This is further proven by the dots shown to Harry the first time he uses it:

A labeled dot in the top left corner showed that Professor Dumbledore was pacing his study; the caretaker’s cat, Mrs. Norris, was prowling the second floor; and Peeves the Poltergeist was currently bouncing around the trophy room.

And also (GOF):

Out in the dark corridor, Harry examined the Marauder’s Map to check that the coast was still clear. Yes, the dots belonging to Filch and his cat, Mrs. Norris, were safely in their office . . . nothing else seemed to be moving apart from Peeves, though he was bouncing around the trophy room on the floor above.

In all those cases, the dots shown to Harry were those that would cause an impediment to Harry's purpose (sneaking around).

Therefore, we can answer all the questions "Why didn't x appear on the Mauraders Map" with a simple answer: It didn't affect whatever they were using the map for at the time. Thus there was no need to show them.

This explains why Lupin didn't see Peter until after he joined with Harry and Ron: because Lupin was keeping an eye out only for Harry, Peter was of no significance and thus the map didn't show him, but after he joined with Harry, it became significant for Lupin's use of the map, and thus the map showed him.

This also explains why nobody saw Moody in Crouch's trunk and Sirius or Rita Skeeter in Animagus form: Because they were insignificant for the map's purpose.

This also why Harry didn't notice impostor Moody as Crouch until he tried looking in Snape's office: Since Snape's office was significant for Harry, the map showed Crouch.

This is further proven by this statement of Fred:

“Right,” said George briskly. “Don’t forget to wipe it after you’ve used it —” “— or anyone can read it,” Fred said warningly. “Just tap it again and say, ‘Mischief managed!’ And it’ll go blank.”

Now, if there are hundreds of dots on the map, who cares if anyone can read it!? But if the map only shows what is necessary for the viewer, if an authority figure would use it, the map becomes quite dangerous indeed.

Answer 5

The first recorded instance of Harry using the map in Goblet of Fire is for his egg adventure:

The Invisibility Cloak would, of course, be essential, and as an added precaution, Harry thought he would take the Marauder's Map, which, next to the cloak, was the most useful aid to rule-breaking Harry owned.

During that excursion the map was confiscated by Crouch/Moody:

Moody waved the map in front of Harry, who braced himself —

"Can I borrow this?"

"Oh!" said Harry.

He was very fond of his map, but on the other hand, he was extremely relieved that Moody wasn't asking where he'd got it, and there was no doubt that he owed Moody a favor.

"Yeah, okay."

So Harry didn't have the map for the rest of the year.

We are also privy to how Harry used the map on the way back from the prefects bathroom until he got stuck and the whole situation with Filch, Snape, and Moody developed:

Out in the dark corridor, Harry examined the Marauder’s Map to check that the coast was still clear. Yes, the dots belonging to Filch and Mrs. Norris were safely in their office... nothing else seemed to be moving apart from Peeves, who was bouncing around the trophy room on the floor above.... Harry had taken his first step back towards Gryffindor Tower, when something else on the map caught his eye... something distinctly odd.

Peeves was not the only thing that was moving. A single dot was flitting around a room in the bottom left-hand corner – Snape’s office. But the dot wasn’t labelled "Severus Snape"... it was Bartemius Crouch.

Here we see that Harry was not looking for very specific things. He checked on Filch and Mrs. Norris, and whether there was any movement. Even if Moody would show up while locked in the trunk, Harry would not have seen him because he wasn't looking for him.

So the question of "Why didn't the map show Moody?" never starts — we simply don't know if the map showed him, but in any case Harry wouldn't have seen him, as the one time that we know Harry used the map he was focusing on other beings.