"In the spirit of this holiday weekend, I want to share the most joyful photo of Beast jumping I've ever seen," Zuckerberg wrote in the caption. "Even after living with this guy for five years, seeing him bounce around still makes me smile. I hope your holiday weekend has been joyful too."
It's been a beautiful five years together. Below are a few highlights from the family's photo collection.
Here's one of the first photos of Zuckerberg and Beast together.