Thanks to Cambridge University's Andy Wheeler for the answer! Like this podcast? Please help us by supporting the Naked Scientists

In this animal-themed edition of the news: What prompted scientists to put vampire bats on a treadmill? Also ahead: why medicinal leeches are returning to the UK's waterways. Plus, the spiders that know what kind of food will satisfy their dietary needs. Like this podcast? Please help us by supporting the Naked Scientists

Why are we called The Naked Scientists? Why should you get sunlight in the morning? Why does bright light make you sneeze? Does luck have a pattern? Is there really such thing as bad luck? Do people who don't get sunlight have more health problems? Did our skin colour change because of agricultural reasons? Dr Chris Smith and Clarence Ford have all the answers... Like this podcast? Please help us by supporting the Naked Scientists

On today's programme, we are going to examine attempts to end HIV/AIDS as a public health threat by the end of the decade.The AIDS pandemic is unarguably the worst health threat to confront the population in the modern era. We believe close to 100 million people have died of the disease so far since it first emerged in the early 1900s.It's proved a very tough nut to crack; when I first went to medical school in 1993, a patient with advanced AIDS and just weeks away from dying came to speak to us.That rarely happens in first world countries these days thanks to breakthrough scientific... Like this podcast? Please help us by supporting the Naked Scientists

Dr Chris Smith answers questions from the listeners of CapeTalk. Including, why are pregnant women told to take folic acid? What causes ears to itch? Why is vomit yellow? Is there a relationship between organs of the body and areas of the skin? How effective is carbon dating? Like this podcast? Please help us by supporting the Naked Scientists

Rick wants to know why the Canada geese he's been observing, who are preparing to migrate for the winter, are honking so incessantly while flying in formation. Viola Ross-Smith from the British Trust for Ornithology was on hand to help James Tytko with the answer... Like this podcast? Please help us by supporting the Naked Scientists

This episode of The Naked Scientists: what's at stake at this year's UN climate summit in Azerbaijan? Also, the 80 million-year-old fossil revealing how birds came by their big brains; and why the UK's oldest satellite has wandered off over the Americas... Like this podcast? Please help us by supporting the Naked Scientists

In this edition of The Naked Scientists, could weight loss jabs help shrink the size of the global obesity crisis... Like this podcast? Please help us by supporting the Naked Scientists

In this episode of Naked Neuroscience, James Tytko is investigating what harms smartphones might be inflicting on adolescents. He hears from a collective action group seeking to delay giving phones to their children, neuropsychologist Richard Cytowic describes the autism-like symptoms which arise from too much screen time, and we hear why a ban on smartphones in schools might be a step too far in mitigating the negative effects. Like this podcast? Please help us by supporting the Naked Scientists

Van writes in with, 'A friend is encouraging me to take a cancer screening test that screens for many different cancers. A review of one test says: "While overall it picks up 90% of stage 4 cancers, it only detects an average of 17% of stage 1 cancers. Yet it is being touted as a test that can detect cancer early." Are these tests worthwhile?' James Tytko took on the question with the help of Professor Rebecca Fitzgerald, Founding Director of the Early Detection Institute at the University of Cambridge... Like this podcast? Please help us by supporting the Naked Scientists