Discovery

Who should be prevented from having children? And who gets to decide? Across 20th century America, there was a battle to control birth - a battle which rages on to this day.In 1907, the state of Indiana passed the first sterilisation law in the world. Government-run institutions were granted the power to sterilise those deemed degenerate - often against their will.In the same period, women are becoming more educated, empowered and sexually liberated. In the Roaring Twenties, the flappers start dancing the Charleston and women win the right to vote.But contraception is still illegal and utterly taboo. The pioneering campaigner Margaret Sanger, begins her decades long activism to secure women access to birth control - the only way, she argues, women can be truly free.In the final part of the episode, sterilisation survivor and campaigner Elaine Riddick shares her painful but remarkable story.Contributors: Professor Alexandra Minna Stern from the UCLA Institue of Society and Genetics, Professor Wendy Kline from

"You will not replace us" was the battle cry of white supremacists at a rally in Charlottesville in 2017. They were expressing an old fear - the idea that immigrants and people of colour will out-breed and replace the dominant white 'race'. Exactly the same idea suffused American culture in the first decades of the 1900s, as millions of immigrants arrived at Ellis island from southern and eastern Europe.The 'old-stock' Americans - the white elite who ruled industry and government - latched on to replacement theory and the eugenic idea of 'race suicide'. It's all there in The Great Gatsby - F.Scott Fitzgerald's novel set in 1922 - which takes us into the world of the super-rich, their parties and their politics.Amidst this febrile period of cultural and economic transformation, the Eugenics Record Office is established. Led by Charles Davenport and Harry Laughlin, it becomes a headquarters for the scientific and political advancement of eugenics.By 1924, the eugenically informed anti-immigrant movement has tri

We follow the story of eugenics from its origins in the middle-class salons of Victorian Britain, through the Fitter Family competitions and sterilisation laws of Gilded Age USA, to the full genocidal horrors of Nazi Germany.Eugenics is born in Victorian Britain, christened by the eccentric gentleman-scientist Sir Francis Galton. It’s a movement to breed better humans, fusing new biological ideas with the politics of empire, and the inflexible snobbery of the middle-classes.The movement swiftly gains momentum - taken up by scientists, social reformers, and even novelists as a moral and political quest to address urgent social problems. By encouraging the right people to have babies, eugenicists believed we could breed ourselves to a brighter future; a future free from disease, disability, crime, even poverty. What, its proponents wondered, could be more noble?The story culminates in the First International Eugenics Congress of 1912, where a delegation of eminent public figures from around the world gather in

Hiding in the shadows across the American continents lives a big cat with many names. From puma to mountain lion to panther to cougar, this animal is carnivorous, cunning and uses stealth to silently ambush its prey. Its elusiveness and brutal attacking style has earnt it the reputation of a cold-hearted killer. But behind this façade, hidden camera footage has revealed the cougar is all about caring for their family. And its silent whispering amongst the trees could actually be saving human lives. Adam Hart and guests uncover the mysteries of the ‘ghost of the forest’ and break its merciless stereotype. Dr Laura Prugh, associate Professor of Quantitative Wildlife Sciences at the University of Washington, and Dr Mark Elbroch, ecologist and director of the Panthera programme in Washington USA.

Why do wasps exist? While many see them as unfriendly bees who sting out of spite, their aggression could be interpreted as a fierce form of family protection. They are hugely understudied and even more underappreciated, with hundreds of thousands of different species carrying out jobs in our ecosystems. Some live together in nests whereas others hunt solo, paralysing prey with antibiotic-laden venom. In abundance, they can destroy environments - outcompeting most creatures and taking resource for themselves - but could we harness their predatory powers to take on pest control? Adam Hart and guests are a-buzz about this much-maligned insect and explore why we should be giving them more credit.Professor Seirian Sumner, behavioural ecologist at University College London, and Dr Jenny Jandt, ecologist at University of Otago, New Zealand.

As a great African predator and a hot-spot on safari, it is hard to believe that only last century, the African wild dog was considered vermin. It's beautiful coat of painted strokes makes it undeniably distinctive. Yet out in the field, this animal is hard to find. Yes, it camouflages easily against the landscape, but years of persecution, bounties and unintentional trappings means it's now one of the most endangered mammals on the planet. Revelations about its reliance on the pack for protection, predation and parenting means every dog matters in its bid for survival. So how can we further stop numbers dwindling? Adam Hart and guests investigate the tools and tales of the magnificent painted wolf.Dr Dani Rabaiotti, zoologist at the Zoological Society of London, and David Kuvawoga and Jealous Mpofu, conservationists at Painted Dog Conservation in Zimbabwe.

Infectious diseases which cause epidemics and pandemics are on the rise.Claudia Hammond is joined by an eminent panel of disease detectives, who spell out why the risks are increasing and most importantly, what we can do to predict, prepare and protect ourselves against potentially devastating new outbreaks.Will the next infectious disease to wreak havoc across the globe again jump from animals, a zoonotic jump across species? Think SARS, HIV, MERS, Zika, Nipah Virus, Lassa Fever, Ebola, Avian Flu, Swine Flu, Mpox and of course the coronavirus that causes Covid-19. The panel is unanimous in their plea for recognition that human health is inextricably linked to both animal health and the health of the environment. Without an understanding that we are part of an ecosystem and that climate change and the loss of biodiversity have a direct impact on epidemic and pandemic risk, we’ll struggle to keep ourselves safe they say.Claudia is joined by vet-turned-virologist Marion Koopmans, Professor of Viroscience at Era

With nicknames like ‘prehistoric monster’ and ‘living dinosaur’, the Komodo dragon has been well and truly judged by its cover. Its gigantic size, razor sharp teeth and deadly attacking power has earned it a vicious reputation. But beneath the scales of this solitary beast are fascinating tales of rapid healing, decoy nests, and virgin births. And as climate change threatens its native Indonesia, can this hostile reptile adapt to living in closer quarters? Adam Hart and guests dig into how a lonely life may be putting the Komodo dragon at risk...Deni Purwandana, program co-ordinator for the Komodo Survival Program in Komodo National Park, and Dr Chris Michaels, team leader of Reptiles and Amphibians at London Zoo.

Alpacas may have been domesticated for thousands of years but their native lands are the steep hostile mountains of South America where they continue to thrive far from the modern luxuries of animal husbandry. Prof Ben Garrod and Dr Jess French delve deep inside this hardy herbivore to unravel the anatomy and physiology that’s secured the success of this extraordinary member of the camelid family of camels, llamas and vicugna.

Prof Ben Garrod and Dr Jess French get under the skin of the harbour porpoise to unravel this enigmatic and shy aquatic mammal’s extraordinary survival skills - from it’s ability to dive for long periods to accurately echolocating its fast moving prey. They join Rob Deaville, project leader for the Cetacean’s Stranding Investigations Programme at ZSL (Zoological Society of London) to open up and examine what makes this animal unique in terms of its anatomy, behaviour and evolutionary history.

One of the world’s large owls by length, the Great Grey Owl is an enigmatic predator of coniferous forests close to the Arctic tundra. It's most often seen hunting around dawn and dusk, when it perches silently at the edges of clearings. But as Prof Ben Garrod and Dr Jess French delve deep inside to understand its true secret to survival, they find the deep feathery coat belies a deceptively small head and body that‘s evolved unbelievably powerful abilities to silently detect and ambush unsuspecting prey.

Zoologist Ben Garrod and veterinary surgeon Jess French delve deep into some amazing internal anatomy to unravel the secrets to survival of some of nature’s iconic animals.They begin with one of the rarities of the cat family – the cheetah, which at just under two metres long, is the world’s fastest land animal capable of reaching speeds of up to 70mph in three seconds. As Ben and Jess reveal, the body’s rear muscles, large heart and nostrils enable it to achieve record breaking accelerations. But over long distances, it risks total exhaustion and predation from larger carnivores and the risk of losing its valuable prey. We hear during the course of this intricate dissection, how it treads a fine line between speed and stamina in the quest for survival.

What do you get if you smash two hydrogen nuclei together? Helium and lots of energy – it's nuclear fusion!Nuclear fusion is the power source of the sun and the stars. Physicists and engineers here on earth are trying to build reactors than can harness fusion power to provide limitless clean energy. But it’s tricky.Rutherford and Fry are joined by Dr Melanie Windridge, plasma physicist and CEO of Fusion Energy Insights, who explains why the fourth state of matter – plasma – helps get fusion going, and why a Russian doughnut was a key breakthrough on the path to fusion power.Dr Sharon Ann Holgate, author of Nuclear Fusion: The Race to Build a Mini Sun on Earth, helps our sleuths distinguish the more familiar nuclear fission (famous for powerful bombs) from the cleaner and much less radioactive nuclear fusion.And plasma physicist Dr Arthur Turrell, describes the astonishing amount of investment and innovation going on to try and get fusion power working at a commercial scale.

Sneezes, wheezes, runny noses and red eyes - this episode is all about allergies.An allergic reaction is when your immune system reacts to something harmless – like peanuts or pollen – as if it was a parasitic invader. It’s a case of biological mistaken identity.Professor Judith Holloway from the University of Southampton guides our sleuths through the complex immune pathways that make allergies happen and tells the scary story of when she went into anaphylactic shock from a rogue chocolate bar.Professor Adam Fox, a paediatric allergist at Evelina Children’s Hospital, helps the Drs distinguish intolerances or sensitivities – substantial swelling from a bee sting, for example - from genuine allergies. Hannah’s orange juice ‘allergy’ is exposed as a probable fraud!Hannah and Adam explore why allergies are on the increase, and Professor Rick Maizels from the University of Glasgow shares his surprising research using parasitic worms to develop anti-allergy drugs!Contributors: Professor Judith Holloway, Professor

Pi is the ratio between a circle’s diameter and its circumference. Sounds dull – but pi turns out to have astonishing properties and crop up in places you would never expect. For a start, it goes on forever and never repeats, meaning it probably contains your name, date of birth, and the complete works of Shakespeare written in its digits.Maths comedian Matt Parker stuns Adam with his ‘pie-endulum’ experiment, in which a chicken and mushroom pie is dangled 2.45m to form a pendulum which takes *exactly* 3.14 seconds per swing.Mathematician Dr Vicky Neale explains how we can be sure that the number pi continues forever and never repeats - despite the fact we can never write down all its digits to check! She also makes the case that aliens would probably measure angles using pi because it’s a fundamental constant of the universe.Nasa mission director Dr Marc Rayman drops in to explain how pi is used to navigate spacecraft around the solar system. And philosopher of physics Dr Eleanor Knox serves up some philoso-

Why are some smells so nasty and others so pleasant? Rutherford and Fry inhale the science of scent in this stinker of an episode.Our sleuths kick off with a guided tour of the airborne molecules and chemical receptors that power the sense of smell. Armed with a stack of pungent mini-flasks, professor Matthew Cobb from the University of Manchester shows Hannah and Adam just how sensitive olfaction can be, and how our experience of some odours depends on our individual genetic make-up.Dr Ann-Sophie Barwich from Indiana University reveals how most everyday smells are complex combinations of hundreds of odorants, and how the poo-scented molecule of indole turns up in some extremely surprising places.With the help of a flavoured jellybean and some nose clips, Hannah experiences how smell is crucial to flavour, adding complexity and detail to the crude dimensions of taste.Speaking of food, listener Brychan Davies is curious about garlic and asparagus: why do they make us whiff? Professor Barry Smith from the Centr

How do winds start and why do they stop? asks Georgina from the Isle of Wight. What's more, listener Chris Elshaw is suprised we get strong winds at all: why doesn't air just move smoothly between areas of high and low pressure? Why do we get sudden gusts and violent storms?To tackle this breezy mystery, our curious duo don their anoraks and get windy with some weather experts.Dr Simon Clark, a science Youtuber and author of Firmament, convinces Adam that air flow is really about the physics of fluids, which can all be captured by some nifty maths. The idea of pressure turns out to be key, so Hannah makes her own barometer out of a jar, a balloon and some chopsticks, and explains why a bag of crisps will expand as you walk up a mountain.Professor Liz Bentley, Chief Executive of the Royal Meteorological Scoiety, reveals how the dynamics of a simple sea breeze – where air over land is heated more than air over water – illustrates the basic forces driving wind of all kinds.Then everyone gets involved to help Ada

DO WE HAVE YOUR ATTENTION?Good! But how does that work!?Our intrepid science sleuths explore why some things immediately catch your eye - or ear - while others slip by totally unnoticed. Even, on occasion, basketball bouncing gorillas.Professor Polly Dalton, a psychologist who leads The Attention Lab at Royal Holloway University, shares her surprising research into ‘inattentional blindness’ - when you get so absorbed in a task you can miss striking and unusual things going on right in front of you.Dr Gemma Briggs from the Open University reveals how this can have dangerous everyday consequences: you are four times more likely to have a crash if you talk on the phone while driving -even handsfree.Drs Rutherford and Fry also hear from stroke survivor Thomas Canning, who developed the tendency to ignore everything on the left side of space, despite his vision being totally intact. And Dr Tom Manly, from the University of Cambridge’s Cognition and Brain Sciences Unit, helps our sleuths unpack the neuroscience of

Chi Onwurah tells Jim Al-Khalili why she wanted to become a telecoms engineer and why engineering is a caring profession.As a black, working class woman from a council estate in Newcastle, she was in a minority of one studying engineering at university in London and encountered terrible racism and sexism. She went on to build digital networks all over the world, the networks that make today's instant muli-media communications possible. And Chi built the first mobile phone network in Nigeria, when the country was without a reliable electricity supply. Today she is Shadow Minister for Science, Research and Innovation.When Chi decided to go into politics, her engineering colleagues were not impressed. Why would anyone leave their noble profession to enter a chaotic, disreputable and dubiously useful non-profession, they asked. But, Chi believes, parliament desperately needs more scientists and engineers, not only to help us solve science-based problems but also to create technical jobs and build a strong economy

Six and a half million dead. More than a hundred times that infected. The Covid-19 pandemic has wreaked havoc across the globe. But in the final months of the third year of this health crisis, some now claim it’s all over.Scientists with key roles in the global response join Claudia Hammond to consider the evidence behind the declarations that the pandemic has finished and they set out how, officially, this global health crisis will be brought to an end. They reject claims that the pandemic is over, but say the emergency phase of this global health crisis is coming to a close. But only if countries remain vigilant and maintain pandemic preparedness.If vaccines reach arms, if treatments are shared equally and if nations re-introduce public health measures like mask wearing and social distancing when the inevitable new waves (and potential new variants) emerge, the appalling loss of life we saw at the beginning of the pandemic, they tell Claudia, won’t be repeated. There are stark warnings too that the dramati