[He should pet them. He most definitely should pet them, and that's not just encouragement from the general narration: one particularly bold dragon that's waddled up to Robert's boot is shouting out his eager desire for attention. Pet me and feed me and love me are all intermingled there, a nonverbal golden cloud that's sent telepathically up to the Luteces, and which boils down to: pay attention to me.

The dragon-- blue, and a little fatter than his siblings-- butts his head gently against Robert's ankle, then looks up hopefully at him.]

To say the least. I've seen green, but never blue or brown. Do you think they have different capabilities, or that it's a purely aesthetic change?