Rooney Mara’s casting as Tiger Lily in Warner Bros.’ upcoming live-action “Pan” feature showcases the challenges facing Native American and other minority performers.

Despite recent blockbusters featuring Native American characters, many of the roles have gone to white performers. In 2013, for instance, Disney’s “The Lone Ranger” generated an outcry after Johnny Depp (who claims Native American ancestry) was cast as Tonto. That decision was defended as the role going to the best available actor, and a similar argument is being used in Mara’s case, too.

“I’ve heard a lot of people saying, ‘Well, maybe this actress is the best person to play this role.’ And I just find it hard to believe that there isn’t a Native American actress who’s just as talented as Rooney Mara. There’s got to be. We just haven’t found her yet, and a lot of that is because there isn’t a lot of opportunity for Native American actors,” said Marissa Lee, a casting diversity advocate and co-founder of Racebending.com. “There are very few roles in film that are written specifically for a Native American, so when an opportunity like this comes around and a Native American actor isn’t cast, it’s very disappointing.”

A petition on Care2.com that tells Warner Bros. CEO Kevin Tsujihara to “stop casting white actors to play people of color” has received more than 8,100 signatures. The studio is staying mum on the controversy—a spokesperson didn’t respond to a request for comment—perhaps because this type of outrage ebbs and flows in the entertainment industry.