Rosie O'Donnell; dog Nicky (inset)
Peter Kramer/Bravo/AP; Courtesy of Rosie O'Donnell
10/15/2012 at 02:00 PM EDT
is mourning a beloved family member.
Nicky, a Lab mix adopted from an animal shelter 13 years ago, died from old age.
"RIP NICKY O BOY – [our] miami born rescue dog – loyal smart nearly perfect for over a dozen years," O'Donnell, 50, Tweeted
The comedian, who recently suffered a heart attack
that nearly killed her, told PEOPLE that the dog was a protective presence in her family, which includes new wife Michelle Rounds
, and children Parker, 17, Chelsea, 15, Blake, 12, and Vivienne, 9.
"One day, when Blake was 2 years old we were all snow tubing on the hill and Blake jumped in the tube and it started going down," O'Donnell wrote in an e-mail. "Nicky put his paws on the tube and held it so Blake wouldn't go down alone."
O'Donnell and Rounds also share two other dogs
– a 4-lb. Chihuahua and a 4 lb. Pomeranian.