Released theatrically on March 14, 2008, by 20th Century Fox, it grossed $297 million on a budget of $85 million. The film is the third Dr. Seuss feature film adaptation, the second Dr. Seuss film starring Jim Carrey after How the Grinch Stole Christmas (2000), and the first adaptation of a Dr. Seuss work fully animated using CGI technology.
A dust speck is dislodged from its obscure place and sent adrift through the Jungle of Nool. At the same time, Horton the elephant, the jungle's eccentric nature teacher, takes a dip in the pool. The dust speck floats past him in the air, and he hears a tiny yelp coming from it. Believing that an entire society of microscopic creatures are living on that speck, he places it atop of a clover. Horton finds out the speck harbors the city of Whoville and its inhabitants, the Whos, led by Mayor Ned McDodd.
He has a wife, Sally, ninety six daughters (whose names all begin with the letter H), and one teenage son named JoJo. Despite being the oldest and next in line for the mayoral position, JoJo doesn't want to be the next mayor, and because he's so scared of disappointing his father, never talks. Once Horton begins carrying the speck with him, the city starts experiencing strange phenomena (earthquakes and changes in the weather), and the Mayor finds his attempts to caution Whoville challenged by the Town Council, led by the opportunistic yet condescending Chairman.
After he makes contact with Horton, the Mayor finds out from Dr. Mary Lou LaRue that Whoville will be destroyed if Horton does not find a "safer, more stable home". Horton resolves (with the help of his best friend Morton the mouse) to place the speck atop Mt. Nool, the safest place in the jungle. The head of the jungle, the Sour Kangaroo, disbelieving Horton's beliefs and resenting him for overshadowing her authority, attempts several times to demand that Horton give up the speck, but Horton ignores her demands. Also taking force toward Horton are the Wickersham Brothers, a group of monkeys who love making misery. Eventually, the Kangaroo enlists a vulture named Vlad Vladikoff to get rid of the speck by force.
Vlad manages to steal the clover away from Horton and drops it into a massive field of identical pink clovers, causing an apocalyptic tremor in Whoville. After unsuccessfully picking nearly three million clovers, Horton eventually recovers the clover (exactly the 3,000,000th clover). The Kangaroo eventually finds out, thanks to Mrs. Quilligan, that Horton still has the speck, and decides to rally the jungle community into fighting Horton, saying that Horton's goal will lead to anarchy. Upon cornering him, the Kangaroo offers Horton an escape from punishment by renouncing Whoville's existence.
Despite Horton's heartfelt speech when he refuses, the Kangaroo orders the animals to rope and cage him, and to have the speck and the Whos destroyed in a pot of boiling beezlenut oil. The Mayor enlists all of his people to make noise by shouting "We are here!", as well as playing a variety of instruments, so the animals may hear them, assisted by JoJo's "Symphonophone", an invention which creates a huge musical contribution (which reveals that JoJo's "true" passion is music), but still fails to penetrate the surface of the speck.
As Horton lies beaten and captured, the Kangaroo easily takes the clover, and drops it. Meanwhile, JoJo grabs the horn used to project Horton's voice, runs up the highest tower and screams "YOPP!", breaking through the sound barrier just seconds before the speck hits the oil.
The Kangaroo's son, Rudy grabs the clover and returns it to Horton. The animals finally hear the Whos and realize the truth and isolate the Kangaroo for tricking them. While being praised for his integrity by his neighbors, Horton even forgives the devastated Kangaroo, and she befriends him with a makeshift umbrella for Whoville. Here, the people of Whoville and the animals of Nool gather in song and recite the chorus from "Can't Fight This Feeling". The film ends with the narrator revealing that the Jungle of Nool, or rather Earth, is just one speck, like Whoville, among numerous others, floating in outer space.Jim Carrey as Horton the Elephant, an outgoing, big-hearted, loving, sweet, and thoughtful elephant and teacher in the Jungle of Nool. Horton has no tusks, lives by himself and possesses acute hearing abilities.
Steve Carell as Mayor Ned McDodd, the mayor of Whoville. He has 96 daughters, 1 son named JoJo and a wife named Sally.
Carol Burnett as the Sour Kangaroo, who mistrusts Horton's inquisitive nature as a threat to her legal authority over Nool.
Will Arnett as Vlad Vladikoff, a Russian-accented vulture hired by the Sour Kangaroo to steal Horton's clover.
Seth Rogen as Morton the Mouse, a mouse and Horton's best friend in the Jungle of Nool.
Dan Fogler as the Chairman of Whoville, dedicated to Whoville tradition and mistrustful of the Mayor.
Fogler also voices Yummo Wickersham, leader of the Wickersham ape tribe.
Isla Fisher as Dr. Mary Lou LaRue, a professor at Who U.
Jonah Hill as Tommy, one of Horton's students.
Amy Poehler as Sally O'Malley, the Mayor's wife and mother to Jojo and her 96 daughters.
Jaime Pressly as Mrs. Quilligan, Jessica's mother.
Charles Osgood as the Narrator
Jesse McCartney as JoJo, the Mayor's son.
Josh Flitter as Rudy Kangaroo, the Sour Kangaroo's son.
Niecy Nash as Miss Yelp, the Mayor's assistant.
Laura Ortiz as Jessica Quilligan, Mrs. Quilligan's daughter and one of Horton's students.
Selena Gomez as Helga, one of the Mayor's 96 daughters.
Joey King as Katie, a cute, but eccentric little baby yak.
Bill Farmer as Willie, a bear and Tommy's dad.
Heather Goldenhersh as Who Girl
In March 2005, as Blue Sky Studios was completing Robots, the studio started courting Dr. Seuss' widow Audrey Geisel on getting the adaptation rights for Horton Hears a Who!. The art director for Robots, Steve Martino, along with story consultant and additional scene director Jimmy Hayward, created a model of protagonist Horton and some animation tests to showcase their design ideas to Geisel, who eventually agreed on "a seven-figure deal" for both the book and its predecessor Horton Hatches the Egg. Cinco Paul and Ken Daurio were then hired to write the script, to be directed by Hayward and Martino with a set release date of 2008.
Geisel was credited as a supervising producer and watched production up close, and also gave the directors full access to her late husband's archives, and thus they investigated on his original sketches, 3-D sculptures, work done for The 5,000 Fingers of Dr. T and even memos Dr. Seuss traded with Chuck Jones during the production of the Grinch TV special. For references in doing the character animation, along with footage of the voice actors performing their lines, the Blue Sky animators recorded themselves performing the script in an "acting room" to see what of their body language could translate well into the film.
To make Horton different from the mammoths Blue Sky worked with in the Ice Age series, the elephant would at times walk on two legs, in a way that it looked like "a fat man in an elephant suit". While the design had a major difference from the original book, with a bigger mouth to allow for wider facial expressions like those of Jim Carrey, as the directors noticed Horton's design in the book varied according to his emotion, the 3D wireframe tried to allow for the same effects.
The original score for the film's soundtrack album was composed by John Powell. A soundtrack, consisting of the film's score, was released on March 25, 2008, by Varèse Sarabande. Near the end of the picture, the cast comes together and sings the song, "Can't Fight This Feeling" by REO Speedwagon.
Others songs featured in the film are:
Review aggregator Rotten Tomatoes reports that 79% of critics gave the film positive reviews, based on 132 reviews. The site's consensus reads, "Horton Hears A Who! is both whimsical and heartwarming, and is the rare Dr. Seuss adaptation that stays true to the spirit of the source material." Another review aggregator, Metacritic, calculated a score of 71 out of 100 based on 31 reviews, indicating "generally favorable reviews." According to CinemaScore, the film version rated an "A-" on an "A+" to "F" scale.
Horton Hears a Who! grossed a total of $297 million on a $85 million budget. $155 million came from the United States and Canada, and $143 million from other territories.
In its opening weekend, the film grossed $45 million in 3,954 theaters, averaging $11,384 per theater in the United States and Canada, and ranking #1 at the box office.
The film previously had the fourth-largest opening weekend in March, behind Ice Age, Ice Age: The Meltdown and 300, and as of September 2012, it ranks on the 15th place. In the United States and Canada, Horton Hears a Who! was also the #1 film its second weekend of release, grossing $25 million over the Easter frame, in 3,961 theaters and averaging $6,208 per venue. It dropped to #2 in its third weekend grossing $17.8 million in 3,826 theaters and averaging $4,637 per venue.
Horton Hears a Who!, like other Dr. Seuss creations, contains layered subtexts and messages. A major theme regards on learning about universal values between vastly different places and people, as shown by the quote "A person's a person, no matter how small". This is employed on many levels, primarily with Horton hearing a world in a speck, while also appearing with the Mayor's relationship with his son, and Sour Kangaroo learning the truth about Horton's beliefs.
The movie characters display traditional gender roles. According to NPR host and father of three daughters Peter Sagal, "In a new subplot added by the filmmakers, the mayor of Whoville has 96 daughters. He has one son. Guess who gets all his attention? Guess who saves the day?"
Dr. Seuss' Horton Hears a Who! was released on DVD and Blu-ray on December 9, 2008. Three versions of the DVD are available: a single disc edition, a 2-disc special edition, and a gift set packaged with a Horton plush.
A Blu-ray combo pack with a DVD and digital copy was released on October 11, 2011. The home media included an Ice Age-related short film, Surviving Sid.
In the United States, the film earned $77,630,768 from DVD sales and $180,434 from Blu-ray sales for a total of $77,811,202 in video sales.