The secret life of the cat, examining the Jekyll and Hyde nature of the feline, which has has been designed and refined over millions of years to be a top ruthless predator.. Filmed in several countries, the program explains what place the creature has in history, asking why it's the most popular domesticated pet in Britain and the USA.The secret life of the cat, examining the Jekyll and Hyde nature of the feline, which has has been designed and refined over millions of years to be a top ruthless predator.. Filmed in several countries, the program explains what place the creature has in history, asking why it's the most popular domesticated pet in Britain and the USA.