With bread prices rising, governments are having to think about upping the circus quotient: hence, the conspiracy theories run, the wedding of Prince William to Kate Middleton; and hence the signing of an agreement this month for Edinburgh Zoo to receive two pandas, Tian Tian and Yangguang. Royalty and pandas have more in common than you might think: both have found their ecological niche shrinking, but have managed to cling on by rebranding themselves as a tourist draw; both have suffered over the years from a failure to renew the gene pool; and this helps to explain why both come under intense public pressure to perform sexually and produce offspring.