[ He's generally excited by all life, sentient and non-sentient alike, by anything and everything. Unless proven to be harmful in some fashion, he's simply fascinated by the universe around him. ]

It's been a very long time since I've seen one myself.

[ He follows her gaze for a moment as she looks towards the rafters, and then he focuses back on her and the dragon she's been tending. Kneeling close to it, the Doctor observes only, but doesn't reach out to touch. He wouldn't presume. He does speak to the dragon, though, addressing it directly: ]

You're beautiful, absolutely magnificent.

[ Looking back at the young woman, he's just as intrigued by her as he is the dragons themselves. ]

Oh, I'd enjoy hearing all about that. You have your own dragon here with you?