Britain faces an epidemic of dog obesity. As many as half of all dogs in the UK may be fat. Using surveillance filming and cutting-edge technology, and working with some of the world's leading experts, Dogs: Their Secret Lives discovers why our dogs are getting fatter and investigates what can be done to help them. Following in the paw steps of three fat pooches - Chancer the Cavalier King Charles spaniel, Molly the bulldog and Cassie the Labrador - the programme reveals how dogs can manipulate us into feeding them and how weight problems can lead to far more serious health issues. Mark Evans explores the challenges facing the 21st-century dog owner and finds out if a scientific approach to food and exercise could help our dogs shed the pounds.

Some dogs are hard to handle and when they show aggression it can be a serious issue for owners. Using surveillance filming, working closely with the UK's leading behaviourists and exploring the latest science, Dogs: Their Secret Lives reveals what can make our dogs aggressive and how to treat them. The programme follows Layla the springer spaniel, Nash the cairn terrier and larger-than-life Great Dane Thor as they bark and growl their way through their daily lives, and finds out how our preconceptions about breed might be wrong and how understanding dog body language could prevent attacks. Mark Evans investigates this growing canine crisis. He meets wolves, finds out whether dogs can pick up on our emotions and takes a dog communication test to find out what can be done to help our more menacing pets.

It's not common to associate dogs with mental health issues but some of our pooches are displaying symptoms, from compulsive behaviours and chronic fears to unusual behaviour like traffic-chasing. Applying the latest technology, using surveillance filming and working with the UK's top behaviourists, Dogs: Their Secret Lives looks into the minds of our dogs and meets three troubled pets - Max, the spinning German shepherd, compulsive bus-chasing collie Biscuit, and Roxy the Staffordshire bull terrier, who's terrified of the great outdoors - to find out what could be at the root of their problems and how to help them. Mark Evans explores the latest brain scanning experiments, meets dogs with incredible learning abilities and finds out about the latest medications as he investigates the challenges facing the 21st-century dog.

Mark Evans presents this live, interactive programme that exclusively reveals the results of the online survey launched earlier in the series.

Mark Evans presents this live, interactive programme that exclusively reveals the results of the online survey launched earlier in the series.

Mark Evans catches up with some of the dogs featured in the series.

Mark Evans catches up with some of the dogs featured in the series.