The Brousseau family adopted Duke the dog six years ago. He was immediately part of the family. When the Brousseau's welcomed the newest addition to their family, Harper the human, Duke was a big brother.

And like a big brother, Duke protected his little sister.

One night, Duke, the typically obedient dog started acting oddly, according to Little Things. Duke jumped into his mom and dad's bed. His severe shaking woke them up. "He is insanely obedient, so this was extremely bizarre," Jenna Brousseau said.

Brousseau folowed Duke to see what was bothering him. He led her into 9-week-old Harper's room. Harper had stopped breathing in her sleep.

Luckily, paramedics arrived and Harper was revived. "If Duke hadn't been so scared, we would have just gone to sleep," Brousseau said. "He's the perfect dog, he was meant, meant to be ours."

For more selfless acts of love, check out more stories from the Pets' Happy Zone like this one.