12 Facts About the Animorphs Book Series

In 1996, Scholastic published The Invasion, the first installment in the Animorphs series. The children’s book opens with blue centaur-like aliens giving human children the power to transform into any animal they touch. They must use their shapeshifting abilities to protect the Earth from the Yeerks, another species of alien that crawls into people’s ears to control their brains. 

Even if you don’t know the extensive lore of the Animorphs universe, you’ve likely seen the evocative covers. The series was inescapable in the late 1990s, and it’s still relevant today: The 2020s have given us a new series of Animorphs graphic novels, and a movie based on the franchise is in the works. Whether you devoured every word of the books or just thumbed through the mini flipbooks in the corners of the pages, here’s everything you need to know about the sci-fi saga. 

1. Animorphs author K.A. Applegate is more than one person.

Many fans know Katherine Applegate as the author of Animorphs, but she created the series as part of a team. She co-wrote the books with her husband Michael Grant under the pen name K.A. Applegate. Both halves of the couple are writers with separate careers outside of the Animorphs universe. Katherine wrote the Endling trilogy and the Ivan & Friends books for young readers, and Michael is the author of the YA series The Gone.

2. Fifty-four books were published in five years ...

Between 1996 and 2001, Scholastic released the 54 books that make up the core Animorphs series. That’s a lot of material, even for a two-person writing team. But Katherine and Michael weren’t working alone. In a 2011 Reddit AMA, Katherine Applegate revealed that books 25 through 52 were ghostwritten. The original authors still had control over the direction of the story, writing detailed outlines for each book, and they returned to write the final two installments themselves.

3. ... And that’s not including spin-offs. 

Hardcore Animorphs readers know that the adventure doesn’t end with the 54 main books. The franchise expanded to included multiple companion series, such as Megamorphs (which switches to a different character’s perspective each chapter) and The Animorph Chronicles (which focuses on the aliens’ side of the story). The world also got its own choose-your-own-adventure-style spin-off series called Alternamorphs.

4. Animorphs was conceived beside a dumpster.

The story behind Animorphs proves that inspiration can strike in the least likely of places. Applegate and Grant were walking around their Sarasota, Florida, apartment complex one evening when they decided to brainstorm ideas for a new children's series. “I wanted to write about animals—to put kids into the heads of animals somehow,” Katherine wrote for Scholastic’s online Animorph’s database the Anibase. “And right there, as we lapped past the dumpster, we got part one of the equation: kids turning into animals. Then we realized we needed some jeopardy.”

They were passed the complex’s dumpster when Grant had the idea to add an alien invasion to the mix, and the story was fleshed out from there. As Applegate put it: “So, Animorphs was born on a hot summer night beside a dumpster in Florida.”

5. The series was meant to be a trilogy.

The story that became Animorphs was always meant to be a series, but the writers initially had a more manageable number of books in mind. The tale was conceived as a trilogy under the title “The Changelings.” Scholastic suggested renaming it Animorphs, which the authors agreed was a better fit.

6. The main cast of characters nearly looked different.

The title of the series wasn't the only aspect that changed during the development process. When drafting the first book, K.A. Applegate didn't immediately come up with the cast of main characters readers are acquainted with today. Jake (named Matt in the early versions) originally had a little brother, and Cassie wasn’t introduced until later drafts. 

7. The authors did their animal research.

Though the story centers on an alien invasion and shapeshifting teens, the authors of Animorphs tried to be scientifically accurate when possible. Katherine Applegate told KidsRead.com that she aimed for authenticity when describing the world through different animals’ eyes. “When Tobias becomes a hawk, I want the reader to see the world as a hawk might see it— to soar on the warm breezes and hurtle toward the ground to make a kill,” she said. “When Marco becomes an ant, I want to convey the ant’s lack of individuality, his blind world of scent and touch. When Cassie becomes a dolphin, I want the reader to feel the water rushing past, to experience what it must be like to leap from cold ocean into warm sky.”

To bring these experiences to life, Katherine did her research. In addition to taking advantage of her library, she talked to zoo curators and zoologists. Her work sometimes brought her face-to-face with the animals she was writing about. In preparation for writing Tobias’s transformation into a hawk, she visited a raptor rehabilitation center and spent time with injured birds.

8. Certain alien words have surprising origins. 

All sci-fi and fantasy writers have their own methods for coming up with fictional words, and parts of the alien language in Animorphs originated from a surprisingly ordinary place: the street outside the writers’ window. “How do I make up names of aliens and so on? Sometimes just by playing with letters and sounds till I get something I like,” K.A. Applegate revealed in a Q&A for Scholastic. “Sometimes I’ll take a word I see around me and alter it or reverse it. For example the Andalite word ‘Nothlit’ came about because I happened to see the word ‘Hilton’ through my window. I just kept re-arranging letters till I got ‘Nothlit.’”

9. The covers borrowed a Hollywood SFX trick.

Many ‘90s kids who never read Animorphs still know the books from their covers; each design shows a character from the series gradually transforming into a different animal. The trippy transitions used a technique called morphing, which combines two pictures into one shape through digital manipulation. The imagery may look cheesy by today’s standards, but it was fairly cutting edge for the time. According to artist David Mattingly, who created the covers for the Animorphs books No. 4 through No. 54, the technology was pioneered by Hollywood visual effects artists before he adapted it for book design. “The first morphing, I think, was in the second Terminator movie,” he told Vice. “I remember it was one of the few instances where [I’d seen] something at the movies that [I’d] absolutely never seen before.” (Mattingly got the gig because he was “one of the first illustrators to switch to the computer,” which led Scholastic’s art director Dave Tomasino to call him. “They knew that they wanted someone to do morphing, so Dave called me up and he said, ‘We heard that you knew how to do morphing.’ I’d actually never done any morphing at all, and I thought, ‘What the hell?’”)

10. Most cover models didn’t return for later books.

In addition to executing the morphing effect, Mattingly shot the photos of the kids and animals that appeared in his covers. Though the five main characters were each the protagonists of multiple books throughout the 54-part series, they weren’t always portrayed by the same cover models. “The kids age too quickly,” Mattingly explained to Vice. “They come back in and they’ve gone through puberty and don’t look the same at all.”

There was one exception. For each of Cassie’s books, the same model was featured in all the cover art. Mattingly said, “If I saw her today, she’d probably look roughly the same—she just never aged, and was a fabulous model, very cooperative.” 

11. The authors weren’t fans of the TV show.

Following the success of the book series, Scholastic adapted Animorphs for Nickelodeon. The show ran from 1998 to 1999, and it featured some questionable special effects and a pre-X-men (2000) Shawn Ashmore. The series has its fans, but the creators of Animorphs aren’t among them. “Oh, we hated the TV series. We felt it insulted the hundreds of thousands of kids who read the books,” Michael Grant said in a 2016 Reddit AMA. If the authors had had their way, Animorphs the show would have been animated. “We told Scholastic we thought it was a bad idea to go ‘live action’ given that animals, child actors, and FX are the three most expensive things you can have in Hollywood, short of hiring Tom Cruise,” Grant said.

12. A new Animorphs movie was announced in 2020.

In 2020, news broke that a movie adaptation of the Animorphs series is coming to the big screen. The new film is a collaboration between Scholastic and producer Erik Feig’s media company Picturestart, which helped adapt beloved YA properties like Twilight, Divergent, and The Hunger Games. The series authors had originally signed on as collaborators, but Michael Grant and Katherine Applegate have since left the project due to “creative differences,” according to Grant, who added in a later tweet, “Decisions we had hoped to be involved in were made without us ... But we have a policy: we don’t claim or accept credit for things we didn’t actually do. Since we weren’t actually doing or contributing anything, we bailed.” Fans are still waiting for more details about the movie, including the cast and release date.