The furrow of his brow is more thoughtful than troubled as he listens to her. Finding, yet again, that he has to expand his understanding of Yennefer, her capabilities, and what is possible in this increasingly strange universe. Magical portals is one thing, time travel is quite another. So he lets himself mull this over a bit before he says anything.

"I'd like to see the dragonfly that used to exist when these animals did," he admits quietly before his enthusiasm raises his voice again. "There was more oxygen in the world then, so even the insects were much larger. Their wingspan was almost a meter long, and dragonflies are the most successful predator in the world. Imagine seeing one that size at work."

Though he only lets himself daydream for a moment before looking at her again. "But I think you're right. Magic is dangerous enough without you going back in time as well. You'd be exhausted, the world would be dangerous, and you wouldn't have any other people to get help from if you needed it."

Which is a rather roundabout way of saying that he'd worry about her.

A dash of movement catches his eye and he sits up in his seat. Taking the binoculars, he scans the undergrowth until he spots what he's looking for. Handing the binoculars over to Yennefer, he points as he directs her. "See there, by the rock and the large fern? You should see an animal with two crests. They're curious animals, and tend to come along to investigate strange sounds."