“It’s unlikely that a group of 10 people, for example, will be successful at colonizing,” said Terry Hunt, an archaeologist and dean of the University of Arizona Honors College. Hunt is a leading expert on the human history of Easter Island and early civilizations in the Pacific Islands.

Demography simulations suggest that groups of 20 or more have a better chance at long-term survival, Hunt said. That’s because having more people minimizes the chance of a skewed sex ratio and prevents the first generation from being too closely related to one another.

But besides wanting a diverse group to avoid inbreeding, the skills people bring to the table should also be diverse. (Let’s face it, brain-eating will get a society only so far.)

“If I were in charge of one of those isolated communities surrounded by timber palisades and sheet metal, I would try to keep as many people with diverse knowledge around as possible,” said Steven Kuhn, an anthropologist at the University of Arizona who studies ancient civilizations in the Mediterranean. “If I had three farmers, I would try to swap one for a potter or a weaver or a chemist.”