A boy, a tiger and a boat. These are the main elements of "Life of Pi," the 127-minute Ang Lee film, released this week, that many are hailing as a masterpiece and a likely Oscar nominee. The 2001 Yann Martel novel the screenplay was based upon, sharing the title, was similarly showered with accolades: It won the prestigious Man Booker Prize for Fiction, and was inescapable on year-end best-of lists.

Both acclaimed, yes, but there are surely differences between what you'll find thumbing through the novel and sitting in a crowded theater. As Martel told The Guardian, changes are inevitable.

“You have to let go," he said. "You have to trust. And it was a crazy and fun ride.”

Here are the differences we spotted between the book and the film.

Massive spoiler warnings ahead.

1. The Opening

Book version: "Life of Pi" opens with a fictitious author's note, beginning with line, "This book was born as I was hungry." The author explains the dips and valleys of his career, and how he came to learn of the main character in his story. Sixteen pages (and descriptions of travels in India and Canada, with mental wanderings to Portugal) later, the fictitious author has thanked many who made the book possible, including the Canada Council for the Arts.

Movie version: After a credits sequence wandering through the zoo where the main character grew up, we cut straight to adult Pi in Canada, telling his story to a man whose character is credited as "The Writer." Here, we get the trailer's most effective line: "This is a story that will make you believe in God."

Level of change: Large.

Good or bad change: Good. We don't have to slog through a long passage that does more to confuse the reader than to set the scene. Instead, we jump right into the story.

2. Pi's education

Book version: Pi begins by regaling us with tales of his double-major Bachelor's studies (religion and zoology) in Toronto, including a lengthy meditation on the "peaceful, vegetarian life" of the three-toed sloth.

Movie version: We only see young Pi in school, pleading with his classmates not to call him "pissing" (a deliberate mispronunciation of his full name, Piscine) anymore.

Level of change: Small.

Good or bad change: Neutral. Adult Pi mentions that he teaches religious studies now, but we don't get to hear as much about his dual fascination with religion and animal nature as we do in the book. It makes where he ends up a little less important.

3. Pi's time in the hospital

Book version: Pi got along well with the nurses and doctors, who left him gifts and cared for him despite their language differences. His condition upon washing up on the beach of Mexico is detailed, sodium levels, leg swelling and all. This is also explained early on.

Movie version: We only see Pi telling the Japanese insurance investigators his stories, at the film's close.

Level of change: Medium.

Good or bad change: Good. It adds some suspense to the story, even though we know he survives, to not see him recovering in Mexico before we have any idea what happened. Also, I was not curious about the color of his urine, which the book helpfully shares. ("Deep, dark yellow going on brown," if you were wondering.)

4. Pi and swimming

Book version: He is painstakingly taught by Mamaji to swim, first by learning the strokes on land, then by swimming laps upon laps in the local pool. His father is also fascinated by "swimming lore."

Movie version: Pi is unceremoniously tossed into the pool by Mamaji, and his father is never mentioned in the same sentence as swimming.

Level of change: Small.

Good or bad change: Neutral. It doesn't make a difference how he learned, only that he can swim.

5. Pi and the zoo

Book version: Pi talks for a while about the ethics of zoos, and whether the animals would like to be free or not, as well as the pleasures of growing up with full access to all the animals.

Movie version: None of this.

Level of change: Medium.

Good or bad change: Neutral. This is just a print vs. film thing. There's not much of a way to fit in Pi's thoughts on cages, and how many scenes of a little kid staring at elephants do we really need?

6. Mr. Kumar

Book version: Pi's biology teacher, Mr. Kumar, is the first atheist he ever meets. They debate religion, and Pi credits him with his decision to study zoology.

Movie version: None of this.

Level of change: Medium.

Good or bad change: Good. The movie focuses more on Pi's journey, less on his theological ponderings. Mr. Kumar was extraneous to that theme.

7. Feeding the tiger

Book version: Pi's father, unprompted, brings Pi and his brother, Ravi, to the tiger cage to "teach them a lesson" about anthropomorphizing the zoo animals. He has starved Mahisha, a 550 lb. Bengal tiger, for three days, before, in front of the children, he has a keeper drop a goat into the cage. The tiger chases the goat around and, of course, rips it apart with his teeth. Pi's father then walks his sons around the zoo and explains how each of the animals could kill them if they're not careful.

Movie version: Pi's brother rats him out for trying to feed Richard Parker, the new tiger, a hunk of raw meat out of his bare hand. His father makes him watch Richard Parker pull a goat through the bars and eat it, though the camera cuts away before the kill shot. Pi's father then lectures Pi about looking into animals' eyes and seeing yourself reflected there.

Level of change: Big.

Good or bad change: Bad. The movie version sets Pi up as a bit of a careless dummy, instead of an inquisitive scholar. It's also a bit heavy handed with the animals-to-humans metaphor that's woven throughout the book.

8. Pi discovers Catholicism

Book version: Pi's family takes a trip to another town, where he wanders into a church and has tea and biscuits with Father Martin, who tells him intriguing stories.

Movie version: Pi's brother dares him to sneak into the church and drink holy water. He then returns again and again to talk to Father Martin, who is kind to him.

Level of change: Big.

Good or bad change: Bad. Movie Pi is, again, kind of a jerk. In the book, he's more curious, less mean-spirited.

9. Pi discovers Islam

Book version: Pi meets a baker in Pondicherry's Muslim Quarter who teaches him about Islam.

Movie version: We don't see Pi being introduced to the religion, he just suddenly has a prayer rug.

Level of change: Medium.

Good or bad change: Bad. There isn't time to linger on each of Pi's discoveries, but it wouldn't hurt to flesh out his explorations a little.

10. "Three wise men" fight

Book version: The imam, the priest and the pandit all see Pi in the city and identify him as part of their religion, then squabble, insisting that one person can't have three faiths. Pi insists that he "just wants to love God."

Movie version: None of this happens.

Level of change: Moderate.

Good or bad change: Good. The movie jumps around in time and location enough without this. We get it: he's religious.

11. The Patels leave India

Book version: Pi's father wants to leave India because he's nervous about owning a business in that political climate.

Movie version: Pi's father says "things will be better for us" in Canada.

Level of change: Small.

Good or bad change: Good. We don't need the descriptions of 1970s Indian politics.

12. Pi's girlfriend

Book version: Pi doesn't have a girlfriend, never attends a dance class and plays no instruments.

Movie version: Pi falls in love with a girl while drumming for a dance class. They "break each others' hearts" when he leaves India.

Level of change: Medium.

Good or bad change: Bad. Really, does everything need to have a romantic aspect?

13. Adult Pi's family

Book version: In an aside from the writer about a third of the way through the book, he describes meeting adult Pi's wife, children and pets. "This story has a happy ending," the writer notes.

Movie version: Pi's family isn't revealed until the closing frames of the movie, when the writer is surprised to meet them coming home.

Level of change: Medium.

Good or bad change: Good. It's a nice surprise, and a good reminder that life goes on, after hearing this traumatic story. One event doesn't define Pi's whole existence.

14. Richard Parker: Manimal

Book version: Pi refers several times to Richard Parker without mentioning that he's a tiger. We think he's a human, not understanding why Pi wants to knock him out with an oar, until he's onboard the lifeboat and is identified as an adult Bengal tiger.

Movie version: Pi points out Richard Parker as the finest animal in the zoo to his girlfriend before leaving India.

Level of change: Big.

Good or bad change: It's hard to say how this reveal would have been pulled off in the movie, but it's such a great switcharoo in the book, it would have been worth preserving somehow.

15. Richard Parker on the boat

Book version: Pi throws a lifebuoy to Richard Parker, who is in the water, and pulls him into the boat before realizing what he's done. Commence freakout. Then, Pi thinks for days that Richard Parker isn't even on the boat, until he makes an appearance on day three.

Movie version: In the calm after the storm, Pi peeks under the tarp. Richard Parker springs out.

Level of change: Adult Bengal tiger-size. Huge.

Good or bad change: Good. It's hard to convey the blind panic that makes Pi help Richard Parker onboard, and the 3-D tiger jumping out at audiences is a great payoff for straying from the novel.

16. The storm

Book version: Pi goes to the deck after hearing the noise of the storm. When he decides to go down to wake his family and sees water below deck, he runs back upstairs for help.

Movie version: Pi swims through the water below deck looking for his family, passing a zebra underwater.

Level of change: Small.

Good or bad change: He still looks for his family in both, but the only real difference is how cool the movie effects look in the underwater scenes.

17. Hyena track meet

Book version: The hyena onboard the lifeboat constantly runs laps around the rim of the boat, cackling and driving Pi slowly insane.

Movie version: The hyena is only in the picture for a few minutes, tops. No lap-running is done.

Level of change: Medium.

Good or bad change: The hyena is much more present in the book, but the few minutes that it was there and making those sounds was more than enough.

18. Hyena attacks the zebra and Orange Juice

Book version: On the second day on the lifeboat, the hyena rips off the zebra's broken leg and eats it. On the third day, the hyena rips a hole in the zebra's stomach and begins eating it, which is described in graphic detail. Orange Juice the orangutan protests, but the hyena doesn't attack her. On the fourth day, Orange Juice and the hyena finally tangle (the zebra is still alive). The hyena kills her, totally beheading her.

Movie version: All of this is condensed, taking place on what seems to be the first day. The hyena attacks and kills the zebra, Orange Juice protests and is then killed. The camera cuts away from the gore, and Orange Juice seems to only have one small wound when she dies.

Level of change: Big.

Good or bad change: Good and bad: It was bad to condense the timeline like that, as if we don't spend enough time hanging out with just Pi and Richard Parker in this movie, but good that viewers are spared what is described in the book as a blood-covered boat and Orange Juice dead and decapitated in a pose like "a Simian Christ on the cross."

19. Richard Parker's backstory

Book version: Seven people in the same area in India were killed by a female tiger. The hunter named Richard Parker set out to kill her and found that she also had a cub, who was at the time drinking from a river. Both the mother and cub were sent to the zoo, and because of a clerical error, the cub was listed on the paperwork as "Richard Parker" and the hunter as "Thirsty None Given."

Movie version: The same story, minus the tiger mother and the killing rampage.

Level of change: Small.

Good or bad change: Neutral. It's a good story behind the name, but there's no point in dragging anyone's mother into this.

20. Death of a hyena

Book version: Richard Parker kills the hyena a day after the hyena kills Orange Juice.

Movie version: All of the animals, save Richard Parker, are killed in one big fight.

Level of change: Big.

Good or bad change: Bad, as decided earlier. The action did not need to be condensed to give us more time to watch Pi crawl around on a boat with Richard Parker.

21. Pi plans to kill Richard Parker

Book version: Pi spends time thinking of ways to kill Richard Parker, including pushing him off the boat, sedating him, attacking him, choking him, poisoning him or starving him.

Movie version: This never happens.

Level of change: Big.

Good or bad change: Bad, or just baffling. Movie Pi seems to adjust pretty quickly to the idea of cruising with a tiger.

22. Taming Richard Parker

Book version: Pi has a moment where Richard Parker reminds him of an oversized housecat, and decides that he must tame him and keep him alive.

Movie version: Afraid of dying, Pi reads in the survival manual how to tame a wild animal and tries to get along with Richard Parker.

Level of change: Medium.

Good or bad change: Bad. The kid grew up in a zoo - it's not totally inconceivable that he would know a thing or two about animal behavior. It's unlikely that the survival guide would have circus training tips in it, and movie Pi has no reason to decide he wants Richard Parker to live.

23. Naked Pi

Book version: From the combination of sun and saltwater, Pi's clothes essentially disintegrate. He goes about his incredible voyage naked, and severely sunburned.

Movie version: Pi has a little self-fashioned turban and a pair of curiously clean white pants throughout the movie. Level of change: Small.

Good or bad change: Neutral, and obviously made for the sake of decency.

24. Food variety and storage

Book version: Pi hangs lines of dried fish all over the place to make sure he always has food, and is also described capturing, killing and eating massive sea turtles and sharks. He also, at one point, tries to eat Richard Parker's feces.

Movie version: We see Pi, previously a vegetarian, fish a few times, crying the first time he smashes an animal's head.

Level of change: Small.

Good or bad change: Neutral. It wouldn't have been too difficult to change things up, but in the end it doesn't matter. A good change: we're spared watching Pi try to eat tiger poop.

25. Whales

Book version: A few whales skim past Pi's boat, one close enough that he worries it will smash the boat with its tail.

Movie version: A hallucinated, acid-green whale leaps out of the water at one point.

Level of change: Small.

Good or bad change: For the sake of 3-D and all that other great movie technology, we'll take it.

26. Ships in the night

Book version: A giant oil tanker comes very close to Pi's boat, but doesn't see him and quickly disappears.

Movie version: This never happens.

Level of change: Big.

Good or bad change: Bad. This was a brief, but surprising moment of hope in the story, then a massive letdown. It certainly wouldn't hurt the story.

27. Message in a bottle

Book version: A bundle of trash from the oil tanker floats by Pi one day, and he puts a message (his name, the ship's name, and the fact that he's on a boat with a Bengal tiger) in a wine bottle he finds, then throws it back to sea.

Movie version: Toward the beginning of his voyage, Pi puts a message in an empty water can, but we don't see what he writes.

Level of change: Small.

Good or bad change: Neutral.

28. Dear diary

Book version: Pi writes his diary until his pen runs out of ink, the last entry simply reading, "I die."

Movie version: Pi's diary blows away in a gust of wind, lost at sea.

Level of change: Medium.

Good or bad change: Bad. How would he have been telling the story to the writer in such detail if his diary was totally gone? He was on the ship for the better part of a year, with no record of it.

29. Blind cat

Book version: Richard Parker goes blind. Pi also briefly loses his sight, then regains it.

Movie version: This doesn't happen.

Level of change:Small.

Good or bad change: Neutral.

30. Tiger talk

Book version: Pi has an extended hallucination in which he has a conversation with a a blind French man in a passing lifeboat, who he thinks is Richard Parker. Richard Parker then eats the imaginary French man. Pi also eats some of his remains.

Movie version: None of this happens.

Level of change: Medium.

Good or bad change: Bad. You would think we'd see a little more of Pi going crazy, if he was supposed to be on that boat for so long (227 days).

31. Fruit tree

Book version: On the carnivorous island, Pi pulls down 32 pieces of fruit, peeling each apart to find 32 human teeth: a complete set.

Movie version: Pi only opens one fruit and finds one tooth.

Level of change: Small.

Good or bad change: Neutral.

32. The insurance story

Book version: A transcript of Pi's entire conversation with the insurance assessors is provided, including their experiments to see whether bananas actually float. (They do.) Pi also steals most of their lunches, and talks about how much he loves chocolate.

Movie version: The story is abbreviated, and no one throws any bananas into water.

Level of change: Small.

Good or bad change: Good that it's shortened, but bad that they don't see if bananas float. Why leave the people wondering?

This is in no way a definitive list - it's a monster of a book and a beast of a movie, and surely viewers and readers will notice new details on each viewing or reread. Did we miss any changes? Do you agree with our assessments? Add your own observations in the comments.