YOU should be afraid of THEM, for once you get too close (usual zoo visitors won't, I should think, but their minders might), they can bite and it is NOT pleasant to be bitten by them!
But they are cute. Meerkats are always cute, as we see so many "human" elements in them, as they tend to be upright (the sentinel always is), and the look around with those big, round eyes.
I like how the "just waking up" comes out so well in your photos. The one in Photo 2 is still sooo relaxed.
My favourite is the sentinel in the bucket, though. I like everything about that one: light, focus, DOF, his posture, everything.