"I'm afraid so." He gave her another smile, looking her over surreptitiously. She didn't seem to be anything unusual, but... something was odd about her, something he couldn't quite put his finger on. "Earth is still rather insular, when it comes to alien species. And dogs, while very intelligent in their own right, aren't sapient just yet. I understand they quite enjoy their walks, leashes or not."
Her eagerness was rather endearing. He found himself smiling again, offering her his arm.
"Would you care to join me for tea, Jenny? I can explain a great deal more, if you like. I'm the Doctor."