I am highly speculating, but strongly suspect they aren't in the game yet due to both size and burrowing mechanics, as well of course a need for a new rig. In fact, I'm wondering if size is not necessarily a factor, but more how they (and any other burrowing animal) interact with the terrain. The few animals we do have that "could" burrow based on real life behavior, do not in the game. So my guess is they're trying to figure out how to get animals to interact with terrain without the game thinking they've escape or actually having them escape.
If that's the case, until that's figured out, they likely won't make an appearance. Unlike aardvarks, and even (for future animals) badgers or wombats, having meerkats would
necessitate having a burrowing function.
Sorry for the long explanation of a speculation. But it's the only thing I can think of logically, as to why such a staple of zoos wasn't included and hasn't been as yet.
(For what it's worth, they've been my #1 most wanted animal since the base game came out. I even have all my zoos that have a global theme having an area I think would suffice for them, just so I don't have to redesign anything, and I know I'm going to want them upfront and center!)
