I'm considering a magical animal companion for a companion character of mine. The animal has been sent by the Divine to protect her. I was thinking about making it a hive of bees. This makes one wonder whether a hive is an animal, or is instead a whole pile of them.
In the game, we can distinguish between individuals and groups by spell target. So assume that I want to cast a spell to affect a hive: is the target individual, or group?
In defense of individual, I'd say that the hive has a much greater coherence than most groups. In a very important sense, it lives or dies as a whole. Plato and Aristotle distinguish these animals from others, and the distinction is just that, for them, the social is more dominant than it is with other animals. Also, there's the metagame reason that bees can act more as a group, and I would hate to have to target each individual bee, or else go up a spell magnitude, to, say, defend myself from them.
One interesting effect of making the target individual is that, if you want to target one solitary bee, you're targeting a part of the hive. I think the aesthetic delight I derive from contemplating this fact is an excellent reason to make the target individual. 
But in defense of group, there's the obvious: it's many bees. And while we're with Plato, in the Republic (Phaedo?)when he's discussing reincarnation, he does have the socially minded man return as a bee or wasp, not as a hive, and its his soul or self that's returning; the soul is the form of the body gives it its intelligibility.
And there's the other possibility that a hive can be a magical animal without being an individual; I can't think of anything positive to say about that, but maybe someone else can.