This undated photograph provided by the Connecticut State Library shows Cpl. J Robert Conroy, of New Britain, and his famed war dog Stubby during World War I. Stubby is the subject of a new animated movie being released on April 13, 2018. (Connecticut State Library via AP)

HARTFORD, Conn. | Curt Deane says his grandfather would be thrilled to know that a century after his service in World War I, people have not forgotten the heroics of his dog, Stubby.

A new animated film based on the true story of the decorated war dog, “Sgt. Stubby: An American Hero” opens April 13.

Director Richard Lanni says he tried to be as authentic as possible when telling the story of the small stray who was adopted in 1917 by Deane’s grandfather, J. Robert Conroy, of New Britain, while he was training in New Haven.

Conroy was able to smuggle Stubby aboard a ship taking soldiers to Europe and, as the story goes, the Boston Terrier mix became the mascot of the 102nd Regiment by charming officers with his ability to salute, a trick which Conroy taught him.

Stubby was never made a sergeant, Deane said. But he did have many documented exploits, earning a medal that was presented to the dog by famed Gen. John Pershing.

“Before Stubby was a cartoon, he was a real dog, and he really did some amazing things,” Deane said.

Stubby was in the trenches during 17 battles, where he was injured in a gas attack and later used his keen nose to give troops early warning of chemical shellings, said Christine Pittsley, who manages the Connecticut State Library’s World War I preservation project. He even had his own custom-made gas mask.

He also would stand by injured soldiers on the battlefield and alert medics by barking. He was even credited with capturing a German soldier he discovered behind the Allied lines, biting him on the rear end and holding on until help arrived, said Pittsley, who helped filmmakers research Stubby’s story.

He also would visit wounded soldiers, including Cpl. Conroy, in field hospitals.

“What I think meant the most to my grandfather is that Stubby took some of the edge off what was a horrific war,” said Deane. “There was just an absolute comfort that soldiers got from seeing him. He was, in fact, the first service dog.”

After he returned from the war, Stubby became famous and toured the country. He posed for photos with celebrities and veterans and met three presidents, Deane said.

Stubby died in 1926. His hide was placed over a plaster cast and is on display at the Smithsonian Institution’s National Museum of American History in Washington D.C., part of an exhibit called “The Price of Freedom: Americans at War.”

Kathleen Golden, who curates that exhibit, said Stubby is popular, especially with teachers who are able to use his story as a way to begin the discussion of the Great War with young students.

“Children can relate to the story of a dog who stowed away and has all these exploits,” she said. “It’s much more interesting to them then just hearing about soldiers and battles.”

Later this month, Pittsley will travel to France with a plush Stubby doll, documenting on social media as she visits the places where Stubby and the 102nd Regiment’s 26th Infantry Division (the Yankee Division), were deployed.

“I want people to get a little more interested in the war,” she said. “I’m hoping this film helps people take another look at the war, especially within their own families and get some of those great intergenerational conversations going.”

Lanni says that is also the hope of the filmmakers, who also have partnered with Humane Society of the United States and approximately 90 other regional and national animal organizations to help promote the adoption of stray dogs.

“We have educators en masse making block bookings to take their kids to this film,” Lanni said. “We really believe Stubby can be a force force for good.”

There will be a Connecticut premiere of the movie April 8 in New Haven. The film features the voices of Logan Lerman, Helena Bonham Carter and Gerard Depardieu.