In my book Soldier Dogs, I describe a magnificent military dog named Rex. He was big and looked fierce, but in reality he was a gentle giant. He had failed the aggression portion of training because any time he bit someone’s protective gear, he’d get this “Oh my God, I’m sorry, are you okay?” look and back off, clearly concerned.

He went on to become an excellent off-leash bomb sniffer, and when deployed, he took on a volunteer gig of sorts: The sensitive fellow made it his mission to comfort the soldiers who were having a rough time.

“He’d always find the one soldier who was having a hard day and hang out with them,” says his handler, Army Sergeant Amanda Ingraham. His favorite form of free therapy was to cheer up soldiers by getting them to play with a water bottle. Maybe Rex reasoned that since he liked playing with water bottles, so would others.

He would take a water bottle in his mouth and trot up to a down soldier and bonk him or her with it. Or he’d sit next to a soldier and crunch the bottle loudly, periodically banging it against the nearest part of his newfound friend. Eventually his “patient” would take the bait, and a grand game of tug of war or a big chase would ensue. Inevitably everyone felt better afterward.

Many military dogs whose stories I learned during my research proved to be phenomenal empathizers. One seasoned old canine veteran helped his new human partner learn the ropes of the job, but he was also there for him emotionally.

“He’s always had my back,” recalls Air Force Staff Sergeant James Bailey. “He was always there to make sure I was okay, whether he needed to help protect me, or when I was a little down and he’d come over and put his head in my lap. He could read my body language, he could read my emotions, like no one else could.”

Of course, I realize it’s not just a military dog phenomenon. Over the years, I’ve experienced this sort of behavior from my own dogs, and I’ve heard about plenty of other compassionate dogs as well.

And now, what so many of us know from experience has been confirmed by science. New research finds that dogs instinctively react to people who appear to be in distress, according to Discovery News.

A study published in the journal Cognition had people — strangers and owners — cry or pretend to do so in front of dogs. Most dogs offered comfort by nuzzling and licking the cryer and acting almost submissively. It’s the canine equivalent of “there, there,” say researchers.

Dogs’ long history with humans has led to this comforting behavior, says study co-author Deborah Custance.

“I think there is good reason to suspect dogs would be more sensitive to human emotion than other species,” she told Discovery News. “We have domesticated dogs over a long period of time. We have selectively bred them to act as our companions. Thus, those dogs that responded sensitively to our emotional cues may have been the individuals that we would be more likely to keep as pets and breed from.”

Makes sense to me. How about you? We’d love to hear your experiences of how your dog seems to know how you’re feeling. Has your dog offered a helping paw when you’re down? Has she made you feel better?

Editor’s Note: If you’re in and around Dayton, Ohio, Maria Goodavage is giving a free presentation on military dogs tonight (Wednesday, Sept. 19) at the National Museum of the United States Air Force. She will be talking, in part, about the empathy factor.