Do dolphins think the way we do or are their brains wired in a very different way from ours? Will we communicate with them one day? Dolphins have been a source of curiosity to humans and have appeared in our stories and myths for thousands of years. What is the link between our two species? Why do we seem to be so interested and curious about each other?

Scientists around the world are asking themselves the same questions. Over the decades the focus on dolphin research has changed from asking 'how intelligent are dolphins?' to 'how are dolphins intelligent?' and we look at research from the world's foremost dolphin experts for the answers.

Horizon investigates the idea that the best way to lose weight successfully is a personalised approach, diets tailored to our individual biology and psychology. In a groundbreaking experiment, Dr Chris van Tulleken and Tanya Byron join a team of experts to put 75 overweight volunteers on diets designed to tackle the specific reasons why they eat too much. The volunteers are put through a series of tests at a residential clinic to understand how their genes, hormones and psychology influence their eating behaviour. They are then put on the diets the experts believe are best suited to them. Can science succeed where other diets have failed?

Evolution tells us that all life exists for only one purpose: to reproduce. But is that all there is? How could such a simple imperative lead us to create great art and civilizations? A new theory suggests that instead of passing on genes, our ultimate purpose is to process and pass on information. We are the universe figuring itself out. Scientists dig deep into DNA, chemistry, technology and engineering to find the meaning of life. One thing is certain: living is easier if you find a reason for living.

Odds are excellent that extraterrestrial life exists. So why haven’t we found aliens out in the galaxy? Are we looking in the wrong places? New research shows we should look closer to home, even inside our bodies. It turns out that a lot of our DNA is from a mysterious, nonhuman source. Theoretically, alien microbial life can make the journey to Earth from distant worlds, and scientists are finding some unearthly microbes in our upper atmosphere. Could it be from outer space? Could we be part alien? It’s even possible alien life is already here as digital life forms, hiding inside our technology.

In ‘Who will we be?’ Dr. David Eagleman journeys into the future, and asks what’s next for the human brain, and for our species. We stand at a major turning point, one where we might take control of our own development. We face a future of uncharted possibilities in which our relationship with our own body, our relationship with the world, the very basic nature of who we are is set to be transformed. For thousands of generations, humans have lived the same life cycle over and over. We are born, we control a fragile body, we experience a limited reality, and we die. But science and technology are giving us tools to transcend that evolutionary story. Our brains don't have to remain as we have inherited them. We are capable of extending our reality, of inhabiting new bodies, and possibly shedding our physical forms altogether. And we are discovering the tools to shape our own destiny. Who we become is up to us.