We always thought it was a joke when Mark Zuckerberg revealed his love of bison meat, when he introduced the Timeline earlier this year. The Facebook founder had pronounced that, "The only meat I'm eating is from animals I've killed myself," but now, thanks to AllThingsD's Kara Swisher, we know that Zuck also decorates with big game he hunts himself as well. Unnervingly explaining how a massive bison head (pictured above) ended up in Sheryl Sandberg's conference room, Swisher reports:

Zuckerberg placed it there recently as a prank, to surprise his top exec with the installation of the very hairy bison when she was away from Facebook’s Silicon Valley HQ. … The bison has now been nicknamed Billy and also sports a Facebook-branded baseball cap and occasional hoodie --natch! (My suggestion if you want to use a dead beast metaphor most effectively here would be to clad it all in Google swag.) 

There's more to the story than a 27-year-old hunting big game and punking his employees, however. Swisher revealed the whole story behind Zuckerberg's bison battle, as Facebook closed the doors on their ramshackle, two-building -- but still very fancy -- Palo Alto headquarters. Over the weekend, movers hustled boxes over to the company's new space in the Sun Microsystems former campus in Menlo Park, near the water of the San Francisco Bay. Employees showed up at the new digs on Monday to mark a new era in Facebook history (and a new home for Billy).

The new era is all about camaraderie, said Sandberg, the victim of Mark Zuckerberg's bison prank. "Literally, the most important thing about this for us is just being together, just the proximity of being able to work together," Sandberg said recently. "I don't think it'll change the company that much, but I think as we grow, having contiguous space can only help communication."

But as those that've been keeping up with Facebook company news already know, the office is poised to become Facebook's first home as a public company. As the social network prepares for a massive hiring spree and an influx in as much as $10 billion in capital, it will tough to hold on to that scrappy startup feel that a ramshackle can offer. It's been estimated that the new campus will host as many as 11,000 employees -- and we'd imagine, fewer pranks involving animal carcasses. Mike Swift at the Silicon Valley Mercury News describes the contrast:

The new campus will feature amenities like a boutique Philz Coffee shop, a stand-alone barbecue shack, and touch screens on the walls that display each employee's work location. But on Facebook's last day in Palo Alto, there was a whiff of nostalgia inside the battered, cluttered spaces the social network has called home.

There are also drawbacks for the surrounding community:

Steve Blank, who teaches entrepreneurship at Stanford, is a critic of what he calls "Fortress Facebook." … "I think it will have the same effect on Facebook as it did on Google. People confuse the amenities with whether it was good for the overall corporate values and culture," Blank said. An isolated campus like Google's or Facebook's "is not great for your community, but it's also not great for your company because you get a monoculture."

We can't help but be a little bit charmed not by Mark Zuckerberg's bison slaying. It's less the idea of Zuck shooting a shotgun at a symbol of the American frontier than it is the idea that the social network that was started on college campuses by college students still somehow manages to feel like a college dorm sometimes. Then again, when you think about the hunting story, the anxiety of a "Facebook Fortress" and the ever evolving role that Facebook plays in controlling how mankind communicates with himself, we're back to being unnerved.