Becky Ripley and Emily Knight dig deep into the underground web of plant roots and mycorrhizal fungi networks. Here lies a 400 million year old market economy, founded on the trading of resources. Nutrients are traded for carbon. Carbon is traded for nutrients. And the exchange rate between the two is constantly in flux, to level supply with demand. This highly-evolved symbiosis between plant and fungi is crucial to the survival of over 80% of all terrestrial plants. And it also acts as a colossal carbon store. A recent study found that 13 billion tons of CO2 are passed from plants to mycorrhizal fungi each year. It's one of the most effective and important market trading relationships in the world. And it turns out, these belowground trade deals are not so different to the aboveground deals that play out within our own market trading economy. Both move and shake to the very same economic principles of supply and demand. Can our economic theories be applied back to the fungi-plant deals in order for the fungi to capture more carbon in the face of climate change? Or, flip-reverse it, can we apply some of their age-old trading strategies to our own economic models? They may not have a brain, but they have 400 million years of evolution under their belt, so their trade strategies may well be more streamlined and more symbiotic compared to ours. Featuring Dr Bethan Manley, fungal geneticist and data scientist at The Society for the Protection of Underground Networks, and Dr Ted Loch-Temzelides, Professor of Sustainable Development at the Department of Economics at Rice University. Produced and presented by Emily Knight and Becky Ripley.

Becky Ripley and Emily Knight explore whether we can ever know what others know, and how we figure out if they're telling fibs. Beneath the surface of the ocean, darting around in the dappled sunlight of the reef, you can find some of nature's most prolific liars. The cephalopods. Squid, octopus and cuttlefish; filthy con artists, the lot of them. They communicate with each other, and with both predators and prey, using dazzling patterns of shifting colour and texture on the surface of their skin. The messages they send can be sophisticated, but they're not always honest; males pretending to be females, octopuses pretending to be sea-snakes, cuttlefish on the hunt for love, pretending to have more innocent intentions. To deceive another, you might think, implies a level of understanding about what that other being knows, or is thinking. The philosophers call this Theory of Mind. But how much do the cuttlefish really KNOW about the tall tales they tell - and how much can we deduce about their intelligence as a result?If cuttlefish are some of nature's best liars, let's meet some of the worst: human toddlers. Oh they lie alright, but they're terrible at it - they tell the most outrageous fibs that we can all see through. That's because they are just beginning to develop the complex skills of Theory of Mind for themselves, and they haven't quite perfected it. How they lie, and how they learn to do it better, gives us fascinating insights into the developing mind of a child.Featuring Dr Jon Copley, professor of Ocean Exploration at the University of Southampton, and Dr Emily Jones, from Toddlerlab, at the Centre for Brain & Cognitive Development at Birkbeck College. Produced and presented by Emily Knight and Becky Ripley.

Becky Ripley and Emily Knight tackle a topic we love to fight about: parenting. How should we raise our kids? How much love is too much?Good parenting begins at home. And 'home', in this case, is a decomposing mouse corpse, rolled into a ball and buried 5 inches beneath the soil of the forest floor. Naturally. This is the home of one of nature's most diligent little parents, the black and orange Gravedigger, or Burying Beetle. The two parents team up to feed, nurture and care for their grubs until they're old enough to make it alone. But is there such a thing as too much parenting? Could a little LESS motherly (and fatherly) love, actually help the grubs be a little more self-reliant?In the human world, we can't seem to agree on the best way to raise our babies. Across time and across cultures, there have been parenting strategies that seem bonkers to us now, while our ways of doing things might raise alarm bells elsewhere. One factor here is that humans spend a lot of time parenting; we're one of the most heavily investing parents the natural world has ever produced. But our babies are needy for a reason: it takes an awfully long time to make a human. Featuring Rebecca Kilner, Professor of evolutionary biology at the University of Cambridge, and Dr Brenna Hassett, biological anthropologist at University College London and the author of 'Growing up Human: The Evolution of Childhood'. Produced and presented by Emily Knight and Becky Ripley.

Becky Ripley and Emily Knight explore the art and science of medicine: What makes you sick? What makes you well again? And how on earth do we (and animals) tell the difference?Deep in the rainforest of Sumatra, one clever orangutan called Rakus has pretty much got it figured out. Astonished researchers spotted him making and then applying a sophisticated plant-based medicinal paste to a painful wound. It was anti-bacterial, anti-fungal, and it numbed his pain, helping him to heal in record time. This might be one of the more sophisticated examples out there, but Rakus is far from the only one; lots of animals are incredibly skilled at using the plants and minerals around them to heal wounds, treat infection, or stave off nasty bugs. It's called, wait for it... zoopharmacognosy. In the human world, we've honed our own medicinal skills into something slick, sterile and very high-tech, but you might be surprised how many of the medicines we use today have natural origins. The age-old skills of the shamans and herbalists of the past are still extremely relevant, and we have yet to fully unlock all the healing secrets of the plants around us.Featuring Dr Isabelle Laumer, cognitive biologist and primatologist at the Max Planck Institute for Animal Behaviour, and Sarah Edwards, Plant Records Officer from Oxford Botanic Gardens and an ethnobotanist from the University of Oxford. Produced and presented by Emily Knight and Becky Ripley.

Becky Ripley and Emily Knight dive into the watery world of rainbowfish to confront the age-old myth that fish have bad memories. In actual fact, they are much more intelligent than we like to think, with an incredible capacity for learning and memory, as seen in almost all fish species. Their ability to remember complex things over a long period of time means they can build social relationships, navigate huge distances, and even form cultures, as knowledge is passed down over generations. So, the science has spoken: fish have way better memories than we like to think. But what about us humans? Well, turns out our memories are way worse than we like to think. From the very first perceptual moment when you experience something, your brain is constantly filtering your memories so that it only keeps the information that it thinks you need. And the more you recount a memory, the more it deviates from "the truth". Which means, in reality, we forget most of our lives, and we misremember most of the rest! Begging the question: are we who we think we are? Featuring Professor Culum Brown, head of The Fish Lab at Macquarie University, and Dr Julia Shaw, criminal psychologist at UCL and author of 'The Memory Illusion'. Produced and presented by Emily Knight and Becky Ripley.

Becky Ripley and Emily Knight return in the series that turns to the natural world to try and make sense of what it means to be human. The new series is available from 29 July

Becky Ripley and Emily Knight tackle a serious question. One of supreme scientific importance: do animals get wasted? From drunk moose stuck in trees, to wasted wallabies asleep in opium fields, to dippy dolphins puffing on toxic pufferfish; stories abound about animals who seem to be using their free time to get sloshed. But do these stories, delightful as they are, stand up to scrutiny? In the natural world, when your survival relies on keeping your wits about you, what could be the evolutionary purpose of dulling your wits with psychoactive drugs? Come to think of it, why do we do it? And what's the connection between getting high, seeing God, and learning to love your neighbour? Produced by Becky Ripley and Emily Knight. Featuring zoologist Lucy Cooke, and Professor Richard Miller at Northwestern University.

Becky Ripley and Emily Knight find out what it takes to learn the language of your people, with the help of some extremely chatty little birds. The song of the zebra finch has been compared to a 90's dial-up modem running triple-speed, or an alien fax machine. But to a female zebra finch, it's a song of irresistible seduction. The males learn their song in a very similar way to the way we learn language, and it all starts with the babies. Through babbling, then copying, then innovating motifs of their own, the zebra finches take their language and then put their own distinctive stamp on it. But if they don't learn it at just the right time, as a chick, they can't learn it as an adult. How does human language acquisition work, and what would happen if you denied a baby the opportunity to learn to speak? The surprising answer takes us to 1970s Nicaragua, and the extraordinary story of the birth of a language... Produced by Becky Ripley and Emily Knight. Featuring Professor Ofer Tchernichovski from Hunter College at CUNY, and Dr Judy Shepard-Kegl from the University of Southern Maine.

Becky Ripley and Emily Knight investigate physical fitness in the animal kingdom, and ask why animals never seem to have to go to the gym. Consider the Barnacle Goose, getting ready for one of the most phenomenal physical challenges of the animal world: the annual migration. They leave their sedentary summer life, floating about eating reeds, and take off to fly 2,700 miles. And what do they do to prepare for this incredible feat? Absolutely nothing. They just sit around, eating as much as they can. The physical fitness of so many animals is hard-wired into their biology. But not ours. If we want to gain muscle, we don't just wait for the seasons to change, we have to work for it. No pain no gain! And if we slack off and laze about, our muscles melt away. Why are we so different? And do I really have to go to the gym? Produced by Becky Ripley and Emily Knight. Featuring Professor Lewis Halsey from the University of Roehampton, and Professor Dan Lieberman at Harvard University.

Becky Ripley and Emily Knight dive into the underwater world of killer whales, where tight-knit family pods are led by the eldest post-reproductive matriarch, to better understand why we have a menopause. Matriarchal killer whales usually stop being able to reproduce in their thirties or forties, but continue to live for decades longer. This phenomenon of having a long post-reproductive life is known only to exist in 5 species: killer whales, narwhals, beluga whales, short-finned pilot whales, and humans. That’s it. Females across the rest of the animal kingdom can keep reproducing into old age, many until their dying days. So why? If the success of a species lies in its ability to breed and pass on its genes, why have we – and a few species of whale – evolved this seemingly counter-productive thing that stops us being able to do that? What's the point of it? And what does it say about our need for grandmas? Featuring Prof. Darren Croft, Professor of Animal Behaviour at the University of Exeter, and Dr. Brenna Hassett, Biological Anthropologist at UCL and author of Growing Up Human. Produced and presented by Emily Knight and Becky Ripley.

Becky Ripley and Emily Knight look to the giggles and guffaws of the animal kingdom to ask where human laughter has come from. At least 65 species have been identified as making 'play vocalisations', a sort of animal version of laughter, according to a recent UCLA paper studying animals at play. Rats giggle in ultrasound, elephants have a play-specific trumpet, and kia parrots cackle from the treetops. These sounds are auditory cues that have come from breathing during play, and they signal to fellow playmates that their rough-and-tumble is in jest. But us humans have taken laughing to new levels. Our laughter has evolved from a play-specific vocalisation into a highly sophisticated tool of communication, sometimes spontaneous, other times performed. It is a powerful spell that affects our brains and bodies, playing so many important roles in our close relationships and wider social networks. And the best thing about it: it’s good for you. Featuring biological anthropologist Sasha Winkler, co-author of the UCLA paper 'Play vocalisations and human laughter: a comparative review' (2021), and Professor Sophie Scott, Director of the Institute for Cognitive Neuroscience at UCL. Produced and presented by Emily Knight and Becky Ripley. Animal recording credits: The chimpanzee laughter clip is courtesy of Dr. Robert Provine. The rat clip (slowed down so that our ears can detect the ultrasound) is courtesy of Dr. Jaak Panksepp. The kea parrot play vocalisation is from Schwing et al. (2017)

Two adventurers delve deep into the myth, legend and reality of the mysterious creature that’s said to roam the Himalayas. This documentary series from BBC Radio 4 follows amateur yeti enthusiasts Andrew Benfield and Richard Horsey as they travel across the mountain range searching for evidence that the yeti might actually exist. Available on BBC Sounds now.

Rhythm is everywhere in the biological world. The rhythm of heartbeat, the rhythm of breathing, the rhythm of gait and walking. In fact, in 'The Descent of Man', Charles Darwin wrote that the perception of rhythm is "probably common to all animals and no doubt depends on the common physiological nature of their nervous system.” And yet, recent studies have shown that even our closest living relatives, the great apes, can't seem to keep a beat. Becky Ripley and Emily Knight investigate. Enter YouTube sensation Snowball the Cockatoo. Much to the intrigue of evolutionary biologists, Snowball loves to dance to anything with a strong beat. Especially The Backstreet Boys. How is it that chimpanzees can't keep a beat and yet this parrot - which is more closely related to a dinosaur than a human - clearly loves to groove? What's going on in the brain of this bird? And how does that link to our own beat-keeping brains? Back in the human world, there's serious neurological benefit to this beat-based research. The more we understand how and why people move to a beat, the more we can appreciate its powerful therapeutic effects. It unites our brains with our bodies, which can help to relieve symptoms of movement-based neurological disorders like Parkinson's, and it unites us to each other. Featuring cognitive neuroscientist Aniruddh Patel and dance psychologist Peter Lovatt.

Becky Ripley and Emily Knight look to the freeze-thaw abilities of the North American wood frog to ask whether we can freeze ourselves in order to return to a future world... Early March is breeding season for the North American wood frog. They are frisky because they’ve just thawed out having spent the winter not just in hibernation, but frozen at -18°C. How do they do it, and still survive? And what can we learn from their frozen ways? Enter the growing field in medicine called cryo-preservation: the process of preserving cells, tissues, or organs by cooling them to very low, or freezing, temperatures. This can grant more time for medical procedures and operations, and help to preserve things like organs during a transplant. And if you take cryopreservation to the extreme, you get to the slightly sci-fi world of cryonics. The practice of cryo-preserving the whole body – immediately upon point of death - in the hope that future medicine can bring it back to life. Maybe in the future, we will crack the code on how to bring bodies back from the cold. And maybe some of the science lies in the freeze-thaw abilities of the wood frog. Or maybe cryopreserved bodies will remain frozen forever… Featuring Dr Allison Sacerdote-Velat, Curator of Herpetology at Chicago Academy of Sciences, and Dr Anders Sandberg, senior research fellow at the Future of Humanity Institute at the University of Oxford. Produced and presented by Emily Knight and Becky Ripley.

You may think 'culture' is one of those peculiar things unique to humans, like dancing to pop music or yelling at the TV. But you'd be wrong. Animals may not flock to the Opera, but they absolutely do have 'culture'; habits; traditions; ways of doing things that are passed down from one generation to the next. Animal culture has been studied in fish, mammals and even insects, and one of the longest-running studies is on a bird you might have spotted flitting around your garden, the humble Great Tit. Becky Ripley and Emily Knight head into the woods, armed with delicious peanuts, to find out more about Great Tit culture. It turns out that these enigmatic birds have long traditions which are shared among the community, and once formed, they can be hard to break, even if they're not serving the birds needs any more. Innovative experiments with puzzle-boxes show that old habits die hard. The one thing that can break the deadlock of tradition and bring back innovative thinking is the arrival of new birds - ones which aren't beholden to the prevailing culture. In the human world, it's well known that an influx of immigrants can have a profound effect on the prevailing culture, often bringing new ways of thinking and innovations in technology, or brand new cuisines. Becky and Emily explore one extraordinary example of this that emerged from the horrors of the Second World War. As German-Jewish scientists fled the anti-Semitic persecution of the Third Reich, they arrived on American shores with plenty to offer the established scientific culture. Featuring Michael Chimento, post-doctoral researcher at the Max Planck Institute of Animal Behaviour, and Professor Petra Moser, professor of Economics at NYU Stern. Produced and presented by Emily Knight and Becky Ripley.

We've all seen the Attenborough documentaries, full of the hurrying and scurrying of life on earth, the drama constantly unfolding. The natural world is a BUSY place... Or is it? The surprising truth is, away from the cameras, most animals spend most of the time doing absolutely nothing at all. It's not just the sleepy sloths and the cat-napping cats, even the critters with reputations for being the most industrious animals on the planet have an astonishing amount of down-time. Peer into the dark warmth of an ant's nest, for example, and you might be surprised to note that just under half of them... don't DO anything. Not a jot. They sit, still and silent, apparently contributing nothing to the colony. Evolution abhors wasted energy so... what's going on? Becky Ripley and Emily Knight search for answers among our insect friends. On the human side of the equation, we're astonishingly bad at doing nothing. We fuss and fidget, we tap our fingers and twiddle our thumbs, trying to escape the horrible fate of being BORED. When animals are so good at efficiently conserving energy, why do so many of us find it so uncomfortable? Perhaps the answer lies in not trying to escape boredom at all, but embracing it, and its creative potential. Becky and Emily discover that it's only through boredom that we can tap in to an extraordinary set of neural processes known as 'The Default Mode Network', and access the most creative parts of our brains. Perhaps doing nothing is more exciting than we first thought. Featuring Professor Dan Charbonneau, behavioral ecologist studying social insect behaviour at the University of Arizona, and Dr Sandi Mann, senior psychology lecturer at the University of Central Lancashire. Produced and presented by Emily Knight and Becky Ripley.

Becky Ripley and Emily Knight ask whether giving legal rights to things like rivers and forests changes how we think about the world that lives around us. The Whanganui River, in New Zealand, is a legal person in the eyes of the law. It is legally defined as a living whole, from the mountains to the sea, and two local Maori tribe members speak on its behalf as its legal representatives. Other nations have had similar thinking: the Amazon rainforest in Columbia, one of the Great Lakes in the US, and the River Ganges in India all have legal personhood, as does land in Ecuador and Bolivia, where Mother Earth is recognised as a legal person. Assigning personhood to non-human things is not a new idea. Since the late 1800s, corporations have been granted legal personhood, giving them the rights to hold property, enter into contracts, and to sue or be sued. Then in 1972, Christopher Stone, himself a Professor of Law, published the essay ‘Should Trees Have Standing?’, arguing that if corporations can have personhood, why can’t natural entities? Does the act of doing this reframe our relationship to the natural world, as something which lives not just for us, but alongside us in its own right? And as the law extents rights to nature, does that - in turn - extend our empathy towards the more-than-human world? Featuring Dr Rāwiri Tinirau, advisor on Māori and Indigenous human rights, and Anna Grear, Professor of Law and Theory at Cardiff University and founder of the Journal of Human Rights and the Environment. Produced and presented by Emily Knight and Becky Ripley.

Why are some sounds more frightening than others? Are there evolutionary origins behind the things we find scary? And is there anything more blood-curdling than a full throated scream? Becky Ripley and Emily Knight tune in to the sounds that send the shivers down our spines, via a frightened Marmot in the Rocky Mountains of Colorado, and a brand new kind of musical instrument known as the 'apprehension engine'. Beware listeners, you may be in for a fright.... Featuring professor Daniel Blumstein, Chair of the Department of Ecology at UCLA, and film score composer Mark Korven. Produced and presented by Emily Knight and Becky Ripley.

As our global society becomes ever more mobile, with people migrating across borders and making new homes among strangers, how do we figure out how to fit in? Trust is the glue that holds society together, but trust - as we all know - must be earned. Becky Ripley and Emily Knight take a trip to the African savanna, to see what a mob of dwarf mongooses can teach us about migration, integration, and making friends across cultural divides. Featuring behavioural biologist professor Andy Radford, and political scientist Marc Hooghe.

Why do we want the things we want? What really drives us? And how in control of our instincts are we? All questions you might ask the humble cuckoo. This dastardly bird - a 'brood parasite' - famously leaves its eggs in another bird's nest and flies off, never to be seen again. The enormous chick hatches, kills all its nest-mates, then runs its adoptive parents ragged with round-the-clock feedings. But why on earth do the poor host-parents fall for the con? To find the answer, Becky Ripley and Emily Knight delve into the history of animal behavioural research to uncover the 'Supernormal Stimulus', a curious phenomenon in which an animal's most basic instincts can be over-ridden, twisted and manipulated, to make them behave in extraordinary ways. Often against their own best interests. And if you think humans are far too smart to be manipulated in this way, think again. Take a look at the things you like, and ask yourself why? Why do you like fast food when it's so bad for you? Why is porn so appealing, when it's so unrealistic? And why can't you put your smart-phone down? Perhaps just like the parasitised victims of the cuckoo chicks, you're not completely in control of what you want. Featuring evolutionary biologist professor Rebecca Kilner and evolutionary psychologist Becky Burch

Becky Ripley and Emily Knight get to grips with fatherhood in the animal kingdom by way of the largest land animal on earth, a fully grown bull elephant. Like the majority of mammals, male elephants aren't directly involved in raising the youngsters - that's left to the matriarchal herd composed of grandmothers, mothers and daughters. But you'd be wrong to think that means they don't have an influence. Via an extraordinary physiological phenomenon unique to elephants, known as 'musth', elephant bulls have a huge role in helping the teenage males navigate their tricky teenage years. And when it goes wrong, tragedy can strike. Back in the human world, dads play a major role in their children's upbringing. Human men are what's known as 'investing fathers', with powerful brain chemistry bonding them to their partners AND to their babies. The skills of fatherhood, which have evolved over millennia, are instinctive, biologically innate and hugely impressive, yet often get overshadowed by our culture's (perhaps understandable) focus on motherhood. Perhaps it's time for a rethink? Featuring conservationist Gus Van Dyk, and evolutionary anthropologist Dr Anna Machin.

What is this thing we call "consciousness"? It feels like a non-physical thing that somehow exists as a separate entity to our physical body. We might think of it as being located up in our brain where our internal chatter is generated, but the 'mind' still somehow feels separate to the 'brain'. Then along comes an octopus to complicate the matter. Octopuses clearly have consciousness and high intelligence. But the last common ancestor between us and them is a flatworm that trawled the sea floor about 750 million years ago, so it's not surprising that their brains have evolved to be very different to ours. In fact, some people say they have nine brains. This is due to a complex neural network that runs throughout their body, meaning they have the ability to make different decisions from all eight arms without having to send messages back up to the central brain. So how can the mind of an octopus be seperate to its body? And does this mean that our mind and body are also one and the same? Featuring writer Sy Montgomery, author of 'The Soul of an Octopus', and philosopher Julian Baggini, author of 'How the World Thinks'.

Sex is simple. Or so we're taught; animals can be male or female. But even the briefest glance at the animal kingdom tells us that this simply isn't true. Some creatures have only one sex; some have three; some have none at all. Some animals are two sexes at the same time; some flip flop between them when the time is right. When evolution came to solve the problem of procreation, she did it in a myriad of mind-blowing ways. When it comes to humans, it's even more complicated - we have this thing called Gender, too. It's often defined as the social and cultural side of sex, distinct from the biological. But that's not the full story. Becky Ripley and Emily Knight travel back to the dawn of human culture, and into the tangled depths of our genetic code, to try and unravel why we are the way we are, and why it matters so much that we understand it all properly. Featuring Professor Jenny Graves, geneticist at La Trobe University, and the writer and scholar Meg-John Barker.

Becky Ripley and Emily Knight celebrate the intelligence of a brainless slime mould. As single-cell protists, with no brain and no nervous system, slime moulds do not 'think' in human terms, but they can calculate and navigate complex systems with incredible efficiency and objectivity. With some help from a few oat flakes, because slime mould loves oats. One species in particular, Physarum Polycephalum, has proven itself to outwit us time and time again, from solving complex urban transport problems to mapping the structures of the cosmic web. In doing so, it totally overthrows our human definition of intelligence, where we have positioned ourselves at the top of a big biological hierarchy. From the bottom up, slime mould is starting to uproot the whole system. Featuring Merlin Sheldrake, writer of 'Entangled Life', and experimental philosopher Jonathon Keats.

Becky Ripley and Emily Knight examine the naked mole rat, a saber-toothed sausage of a rodent, which seems to defy the mammalian laws of aging. It lives way longer than what is expected of a rodent and is now the focus for much medical research as scientists try to understand more about their aging process in the name of human life extension. Of course, we all want to age slower and live longer, but does that mean we should continually strive to extend human life expectancy forever and always? Beyond the ethics, there's also some big philosophical questions. How does a longer life span affect our sense of 'self'? And does living longer solve the problem of death? Featuring Dr Rochelle Buffenstein, Senior Principal Investigator at Calico Life Sciences, and Julian Baggini, philosopher, journalist and author.

Becky Ripley and Emily Knight find out what ants teach us about surviving a pandemic. As social animals, we're particularly susceptible to disease, so perhaps there are lessons to be learned from other sociable species in how we manage this. Ants are one of the most social species on the planet, and it turns out they know a thing or two about self-isolation and social distancing. The story of how we protect each other (and ourselves) is a story that takes us from the complex maze of an anthill to the equally complex maze of human etiquette. If you think social distancing is a new invention - or even a human invention - think again. Featuring Dr Nathalie Stroeymeyt, Senior Lecturer at the University of Bristol, and Michael de Barra, Lecturer in Psychology at Brunel University London.

Naturebang is back. Becky Ripley and Emily Knight are again trying to make sense of what we humans are all about, with a little help from the natural world. And this week, they’re getting lost. Navigating our world is a challenge faced by every creature that moves. From dung beetles mapping the desert dunes, to eels circumnavigating the globe, each finds its own way about with unerring accuracy. How do they do it? And how is that going to help Becky and Emily get out of the woods? The story of animal (and human) navigation is a story of the sun, the stars, magnetic fields, polarised light, and… dog poo. Yes, dog poo. Featuring Michael S. Painter, Assistant Professor at Barry University, and John Edward Huth, Donner Professor of Science at Harvard University.

Ah, true love. Who can quantify that heady rush, the joy of another’s company, the unshakable bonds between one lover and another? Well, vole experts can. This tiny rodent is not just an anagram of love, it can also teach us a lot about why we fall. And why we sometimes stray. Prairie Voles form lifelong monogamous bonds, together until death they do part. Almost identical Meadow Voles don’t, living the single life, and mating at will. It all comes down to brain chemistry. And it turns out, some of us are more Prairie Vole than others. Featuring Dr Larry Young from Emory University, and author of 'Sex at Dawn', Chris Ryan.

If you think you’re in control, think again. What invisible forces might be guiding your behaviour, your decisions, your most intimate emotions? Becky Ripley and Emily Knight take a trip into the bizarre nightmare world of the undergrowth, and watch ‘zombie ants’ stumble forward, blindly following the orders of the deadly fungi controlling their brains. Parasites often get the upper hand of their hosts, manipulating their behaviour in sometimes horrifying ways. But is that true of humans too? Could we be unknowingly subservient to creatures that live inside us? Do they wish us well, or might they be plotting our downfall? Featuring entomologist Dr David Hughes from Penn State University, and neuroscientist John Cryan from University College Cork.

Strange things dwell out in the open ocean. Bobbing atop the waves, Becky Ripley and Emily Knight meet one such creature, the Portuguese Man O’War. With its bulbous air-sacs and trailing tentacles you’d be forgiven for thinking it’s a jellyfish, but you’d be wrong. It’s a colony, a society of tiny individual animals, who work together to eat, hunt and reproduce as one. In the Age of the Individual, we humans like to think of ourselves as self-sufficient little nodes who don’t need nobody. But that perspective gets called into question when you consider where we live. Thanks to some complex maths and some incredible data-crunching, we’re beginning to see the cities we inhabit in a different light. They grow, move, breathe, and die, just like a living organism, according to strict mathematical principles. Just like polyps in a Man O’ War, are we really any more than cogs in a machine? Featuring Marine Biologist Dr John Copley from the University of Southampton, and Geoffrey West, Theoretical Physicist from the Santa Fe Institute.

The humble sea sponge has been around for over 500 million years. We may think of them as ‘simple’ animals, with no brain, no nerves and no organs. But they have a pretty good party trick up their fleshy sleeves. Push a sponge through a mesh, until all that remains is a cloud of cells. Pour those cells into a tank, and watch as the cells reform themselves, like the terminator, back into a sponge. Becky Ripley and Emily Knight ask: is it the same sponge it was before? In the human world, nobody is queueing up to be forced through a discombobulating mesh. But enter the world of science fiction and there’s something that’s not far off… the teleportation machine. Would you allow yourself to be dissolved into a molecular cloud and flung through space and time? And would the ‘you’ at the other end really be the same ‘you’ that left? Featuring Professor Sally Leys from the University of Alberta, and Philosopher Charlie Huenemann from Utah State University.

Starling murmurations, those swirling, shifting sky-patterns made by hundreds of birds moving in synchrony, are one of nature’s greatest spectacles. How do they avoid crashing into each other? Becky Ripley and Emily Knight delve into the maths behind the movement with some computer modelling to help them chart the flight patterns, and discover the secret. As for us humans, sadly we don’t fly together through the sky in swirling clouds. But there are patterns to how we interact with one another. Like a ripple of movement, travelling through a cloud of starlings, ideas can spread through social media with blistering speed. Here too, computer modelling can help us chart how opinions morph as we react to those around us. Do we have more in common with the birds than we think? Featuring Jamie Wood from the University of York, and Dr Jennifer Golbeck from the University of Maryland.

Becky Ripley and Emily Knight look to the natural world to answer some of life's big questions. Science meets storytelling, with a philosophical twist.