Which one's the big one?

(spoilers: it's this one)

The Velociraptor referred to as "The Big One" is a pretty memorable creature in the JP franchise, even though the movie she appears in never actually clarifies which one of the raptors she is in each scene. Being the only named - or at least nicknamed - raptor in the movie and responsible for a lot of the species' scary reputation, it's understandable for fans to want to credit her for all of the most notable on-screen raptoring, but we can't really know for sure. There is, however, grounds for some educated guessing.

She could be the raptor in the opening scene, who kills poor Jophery in a gruesome manner and kickstarts the plot of the movie, due to his death being the reason Hammond needed to invite experts to assess and hopefully endorse his dinosaur park. It would be fitting - she's the first raptor, and in fact first dinosaur we are introduced to. The raptor and Muldoon briefly lock eyes during the scene, which could very well be foreshadowing for their later confrontation (assuming she's that raptor, too, but I think most of us do assume).

Muldoon gives the order to shoot the raptor, though, and we do hear gunshots right at the end of the scene. This could mean the raptor in the opening scene was killed, but not necessarily. If The Big One had killed all but two of the other raptors before they were moved to the smaller holding pen (and moving them to the holding pen is what's depicted in the opening scene), there should then have been only two raptors left for the rest of the events of the movie, but we do see there are three. In retrospect the opening scene's raptor could have been brought from Isla Sorna in attempt to replenish the raptors' numbers after The Big One unexpectedly decreased the population. But of course, Isla Sorna did not exist in the JP lore until two years later, when Michael Crichton wrote the sequel novel set there, so that can't have been the filmmakers' intention at the time. Jurassic Park: The Game does have five more raptors be on Isla Nublar during the events of the first movie, quarantined and indeed brought from Sorna with the intention of later introducing them into the pack, but JP:TG came out in 2011, so that's a retcon, too.

I think a likely explanation is that the gunshots were simply not aimed at the raptor, and were an attempt to scare her into letting go, because Muldoon is not in charge of the whole park and maybe the crew were not actually authorized to kill her. That policy costs Jophery's life, but then again Jurassic Park being run perfectly was far from the impression we were meant to get.

I haven't been keeping up with the Pirates of the Caribbean movies,
but I'm pretty sure they still don't eat tourists in those. Maybe.

If so, yes, the raptor in the opening scene could indeed be The Big One. Although that's assuming Muldoon was telling the truth about The Big One having only left two other raptors alive, and maybe the people invited to be persuaded into endorsing the park haven't been given a completely truthful version of what the events leading to the park needing to be endorsed were, namely that a park worker died. Mentioning that there was a fourth raptor, too, could prompt having to explain why there isn't anymore, which Muldoon might be happy to do but perhaps isn't contractually allowed to. If this is the case, then of course the raptor in the opening scene would not be The Big One. With neither scenario officially confirmed or denied, I think the raptor's identity remains up to interpretation and to which fan theory one prefers, too.

What about when they escape? By the time the audience finds out, one of the raptors has followed Ray Arnold into the maintenance shed and killed him, and ambushes Dr. Sattler there. The other two stalk Muldoon outside.

Despite the nickname, the raptors are not noticeably different sizes, but the script does refer to the raptor in the shed as "the biggest of the raptors". She's the first raptor we see properly, so sure, The Big One could be that one. The nickname might not necessarily refer to the animal's physical size, though, and I've seen it suggested Muldoon, who gives her this nickname, means it as "the big one in charge". And either way, the script's description of the raptor's size doesn't carry over into the film, so even if The Big One is indeed a bit bigger than the other two, the raptor in the shed is alone with no one to compare her size to, so we don't know for sure.

Muldoon: That one, when she looks at you, you can see she's working things out.

As I already mentioned, I think most fans assume The Big One is the raptor that kills Muldoon. He's been more aware than his superior(s) of how dangerous the raptors are and has been expecting a confrontation with them, observing in horror their plotting of their escape and aware they're watching him right back. He's basically made The Big One his nemesis, that he'll eventually have to kill or be killed by. He knows how uncontrollable they are, but a moment of thinking he might pull this off and outsmart them after all is all it takes for them to take advantage of his underestimating them. And also the raptor head emerging from the bush is just such a cool shot, why wouldn't it be given to a notable raptor.

I agree that probably is her. Her behavior in the scene is very in line with what Muldoon tells us earlier, about her getting her packmates that she views as subordinates to attack the electrified fences for her, instead of having to deal with the pain of electric shocks herself. She is using one of her packmates as bait, and collects the prize herself while the bait watches and waits for scraps.

Here's where it starts getting more confusing again. The two raptors in the kitchen scene are probably the two who set a trap for Muldoon, with the one in the shed taking a bit longer to get out. Opening doors is a skill they can learn, but not automatic, and perhaps the raptor followed Arnold into the shed through a door he left open behind him.

The Big One being the raptor who gives Rexy her distinct neck scars is a popular idea, I think. But the raptor she kills first also has that cool entrance, where everybody else is focusing on the other raptor and Dr. Sattler is the first to notice that uh-oh, they're surrounded. On the other hand, the other raptor is the one who chased the humans to the control room and has all that screen time. And the raptor Rexy kills first is probably the one from the shed, joining the party late after finally getting out and unknowingly leading Rexy into the building, so she wouldn't be the same raptor who killed Muldoon. So which is it?

Neither. The Big One never meets Rexy, because she is the raptor Lex and Tim lock in the kitchen freezer.

It's easy to get mixed up in the movie which raptor in the kitchen scene does what, but they were each played by an actor in a raptor suit in this scene, who had to keep track of where each of them would go. In the layout for the scene that marks where each character would go on the set, the raptors are labeled as "Kim" and "Randy", probably because that's more fun than just calling them raptor A and raptor B (though ironically the raptors that do end up getting names in later movies are technically named just B, C, D, and E). Her route marked in green in the layout, Randy is the raptor that enters the kitchen first, and then moves between the counters tapping her claws, closer to where the kids crawl on the other side, and pops her head through the gap in the counter after a swing of her tail knocks stuff off the counter. After the soup ladle that drops to the floor near Tim alerts the raptors to the likely location of their prey, Randy jumps onto the counter while Kim walks alongside her on the floor. Kim then charges at Lex's reflection and gets knocked out for a moment. Randy follows Tim into the freezer, where her part in the movie ends, while Kim recovers from hitting her head just in time to see the kids run out of the kitchen, and goes after them.

A couple of behaviors during the scene lead me to believe the raptor labeled as Randy is The Big One.

She calls the other raptor there, which is something a pack leader might do, but not necessarily just the pack leader. More importantly, when the other raptor shows up, the one who was there first snaps her jaws at her, perhaps for not getting there quicker, or for bumping into her a bit while walking through the doorway she was partially blocking. From what I can tell, the snapping is a behavior raptors higher up in the pack hierarchy do at those lower in it, as reprimand, or if it's the other way around it gets treated as a challenge. The other raptor in the kitchen scene reacts to being snapped at with what looks like submissive behavior - she hisses, but she shrinks away from the other raptor and lowers her head, and she doesn't snap back.

When Lex gets the raptors' attention and they prepare to charge at her, it looks like the one on the counter is communicating something to the other one. Since Kim is the one that does the charge, I'm guessing she was told to by her superior, who intended to sit back and watch her do all the work, or perhaps in a more sympathetic interpretation, was given permission to have that prey to herself. Or, like she'd rather the others get hurt by the electric fence instead of her, perhaps The Big One could tell they were being baited for some reason, and preferred to send her subordinate into the possible trap instead of finding out herself if it is one.

But trapped is how she ends up anyway. All of the raptors die, but she probably does so last, alone, either of hypothermia or starvation/dehydration. A suitable villain death, but not without an element of tragedy, considering she is at the end of the day just a dysfunctional animal, who never learned to form proper social bonds with and trust others of her kind.