I just bought one, Zoo, and I couldn't put it down. I see he is pushing 300 million books sold and has written over 100! This dude must start typing at 6 AM and stops somewhere around midnight!

He talked about pheronomes and I found this online, he mentioned this in the book:

http://phys.org/news/2014-04-territory-pheromone-code.html

In particular, a pheromone sensor in most mammals but not in man, the Vomeronasal organ or VNO which we don't have. He did his research.