No race for the animated feature Oscar has been as dominated by sequels since the category’s debut in 2001 as this year’s. Leading the conversation are big-studio front-runners “Toy Story 4,” “How to Train Your Dragon 3” and “Frozen 2.” Lower down the card, “Secret Life of Pets 2,” “The Lego Movie 2” and “Angry Birds 2” are also vying for a nomination — testing the Academy’s appetite in this category for sequels, which pose unique challenges for filmmakers.

“Sequels can definitely be a double-edged sword,” says “Toy Story 4” director Josh Cooley, who took the Oscar-winning franchise to new locales and added characters, as well as spotlighting Woody’s one-time love interest, Bo Peep. “There’s a world that’s already been established, the characters and tone have been established, but the difficulty is that you don’t want to just copy the same exact thing that’s been done before. With a sequel, it’s about expanding upon what’s already known. It’s a fine balance between doing the same thing you’ve done before and doing something new but in the same flavor. And based on my experience, that tightrope you walk gets smaller and smaller the more sequels you do in a franchise.”

Disney’s “Frozen 2,” which arrives in theaters Nov. 22, may be just as hotly anticipated by fans of the original 2013 film, which won the animated feature Oscar and made more than $1 billion at the global box office to become one of the highest-earning animated features of all time.

“It’s the first musical sequel that Walt Disney Animation Studios ever tackled, so we were in uncharted territory,” co-director Chris Buck says. “Since our main characters — Anna, Elsa, Kristoff, Olaf and Sven — were already established in the first film, the challenge was finding a way to let them grow without losing their distinct personalities. We pushed on every aspect of the film with that same guiding principle: the songs, score and visuals had to feel like the first film, but more mature.”

DreamWorks Animation’s “How to Train Your Dragon: The Hidden World,” meanwhile, is the closing chapter of a beloved franchise that has yet to strike Oscar gold. Writer and director Dean DeBlois charted the trilogy’s story arc early on, allowing the characters to age — and evolve — as the narrative unfolded.

“By the end of the first movie, Hiccup had attained all of the things he wanted, just not in the way he expected,” DeBlois says. “He had gained his father’s love and admiration, the respect of the town, and the attention of Astrid. He ended up with a super-cool dragon and put an end to an age-old war. So he really wasn’t a character with much of a problem. But by advancing the clock and meeting him five years later at another kind of pivotal crossroads, there seemed to be a story to be told as part of Hiccup’s larger coming-of-age.”

From Illumination Entertainment and Universal Pictures, “The Secret Life of Pets 2” tapped comedian Patton Oswalt to voice the lead role of Max, and shuffled the ensemble cast between three storylines. The first film became the fifth-highest-grossing original animated film in history when it was released in 2016, setting raised expectations for the sequel, but Oscar-nominated director Chris Renaud insists he didn’t dwell on that aspect.

“You really just set out to tell a great story with these characters that you have come to love and you truly hope the audience will find something to love as well,” Renaud says. His goal was to retain what resonated with audiences while finding other territory to explore. “This includes new concepts, characters and environments. So, the main challenge is working to find ways to not repeat yourself. We had to really search for new situations in order to fully express those great, relatable pet behaviors in distinct and fresh ways.”

The Academy famously denied Warner Bros.’ “The Lego Movie” an Oscar nomination in the animated category following its release in 2014 despite racking up nominations — and wins — for every other eligible honor, including an Annie Award and two BAFTAs. Praised for its visual style and humor, “The Lego Movie” may not have secured a nomination — although it did receive a nom for original song for “Everything Is Awesome” — but it launched a major franchise with spinoffs “The Lego Batman Movie” and “The Lego Ninjago Movie,” in 2017, and this year’s “The Lego Movie 2: The Second Part.” Directed by Mike Mitchell, “Lego 2” was produced by powerhouse duo Phil Lord and Christopher Miller, but with so many other sequels crowding the field the Minifigs may be overlooked yet another time.

In a race led by CGI sequels, Aardman’s stop-motion animated “A Shaun the Sheep Movie: Farmageddon” might have been a welcome change for the Academy, which to date has favored the U.K. studio with four wins and 10 nominations, including three best animated feature noms. But the film, which will be released stateside on Dec. 13, wasn’t submitted for consideration.

Nominated for two People’s Choice Awards, Sony’s “The Angry Birds Movie 2” was a hit with critics, many of whom found the sequel an improvement over the first installment. Going into the project, director Thurop Van Orman sought to transform the franchise, which is based on Rovio’s popular mobile game.

“Making a sequel is pretty hard, especially when there’s a preexisting movie and a game that you have to service. Coming into it, my goal was just to make a better movie, something that you wouldn’t expect,” he says. “Really, it’s an original story — it’s not playing off of the
first movie or trying to service the video game too much.”