NEW YORK - One of the best things for Kate Mara about starring in Megan Leavey was Varco the dog.

Varco is the Rex to Mara's Leavey in the true story of a young Marine corporal and her fight to bring her combat dog home after service in Iraq.

"He and I trained together, so by the time we started shooting we were very comfortable with each other," Mara says in a recent interview.

"They're unexpected and constantly doing things that you're not expecting them to do. If you want them to just sort of sit there during a scene they will, but then they'll do some genius little movement or sound or whatever that will make the scene that much better," she says of working with dogs.

Mara, an animal activist who has worked with both Oceana and the Humane Society, also had the rare treat of being directed by a woman, Gabriela Cowperthwaite. She had also directed the orca-abuse film Blackfish. In fact, Mara says, her animal advocacy blossomed due to the film.

"Animals really do teach us empathy and compassion and so many other things," she says.

It's that bond between a lost human, Leavey, and a scarred bomb-sniffing dog, Rex, that plays out for Mara.

"I instantly felt connected to it for that reason," she says of the film. She found it refreshing to work with a woman at the helm as well.

"I've been acting since I was 14 and I would say in the past three years I've worked with more females than I ever have in my entire career, and that's directors but also actors," Mara says. "And we had so many females on our crew as well, so I definitely think that's changing. I think it's slower than we'd all like but it makes me so happy that something like Wonder Woman is actually proving that fact. It'll make it easier and easier to make more and more films."

As for dogs, she has two of her own, both Boston terriers. At 14 and 15, she says, "They're doing really well."

Mara recently got engaged to Billy Elliot actor Jamie Bell, but she was tight-lipped about her nuptials.

One of the wedding challenges: She's vegan and Bell's not, "so you've got to make everybody happy".

The film, which opened on Friday, covers raw territory for veterans coping at home with post-combat trauma. Mara wanted to get it right, leaning on her previous role as the wife of a vet in the 2015 release Man Down.

Associated Press