The Obama family and many people across the country are grieving today.

A good dog crossed the rainbow bridge today.

The Obamas are mourning the loss of their beloved dog Bo, a Portuguese water dog belonging to the former first family since Barack Obama's inaugural year in the presidential office.

"Today our family lost a true friend and loyal companion. For more than a decade, Bo was a constant, gentle presence in our lives—happy to see us on our good days, our bad days, and everyday in between," said Barack Obama in an Instagram post.

Bo had been battling cancer, explains Michelle Obama in her own Instagram post in homage to her pup. Bo was 12 years old.

"On the campaign trail in 2008, we promised our daughters that we would get a puppy after the election. At the time, Bo was supposed to be a companion for the girls. We had no idea how much he would mean to all of us," says Michelle Obama in her touching tribute.

She continues, "As a family, we will miss Bo dearly. But we are thankful that he lived such a joyful life full of snuggles, games of fetch, and evenings spent lying on the couch. We also know we weren't the only ones who cared for Bo, and are grateful for all the love you showed him over the years. Please hug the furry members of your family a little closer tonight—and give them a belly rub from us."

The Obamas originally received Bo as a puppy in April 2009 as a gift from Senator Ted Kennedy. After the family had been looking for a shelter dog to rescue, Kennedy gifted Bo to the the first family after the pup had been returned to a breeder in Texas (where he'd gotten one of his own dogs from) and needed to find a loving home. The Obamas later added Bo's sister Sunny, another Portuguese water dog, to their family in 2013.

Bo was a constant presence in the Obama family's lives throughout the former President's two terms in office and beyond. "He was exactly what we needed and more than we ever expected. We will miss him dearly," says Barack Obama in his post.