Charlie didn't answer the young woman right away; instead, he seemed to be thinking over her answer. There was a soft 'hmph' as he apparently came to accept this particular pack theory; truth was he understood it. He'd had to learn it in prison and in the world outside. Living beings tended to like to live in groups; most creatures were social. He supposed it made sense.
Finally her question reached him...
"They're a type of animal. Emus are birds, and leopards are cats." It wasn't the best answer, but still. "They probably wouldn't want to live together; well, the emus probably wouldn't want to live with the leopards. I don't think the leopards would mind sharing living quarters with the emus - they'd probably just eat them though in the long run."