A species of ancient human with a brain the size of a chimpanzee’s is upending what we thought we knew about human cognition and culture. Recent findings from Lee Berger and his team of palaeontologists suggest our extinct relative, Homo naledi, may have engraved symbols on cave walls and deliberately buried its dead. These people lived some 300,000 years ago and the team discusses the dramatic new findings.Air quality across northern parts of the United States, including New York City, has reached dangerous levels following record-breaking wildfires in Canada. The team in London chat with New York-based reporter James Dinneen about the implications of climate-change-induced events like these. Think a flower can’t be scary? Think again! Rowan meets botanical horticulturalist Arnau Ribera-Tort at Kew Gardens in London to discuss the beautiful and ghoulish Ghost Orchid - a plant with no leaves and sheet-white flowers that appear to float in mid-air, and which is blooming in the UK for the first time. Pregnancy sickness is not just unpleasant, it can be dangerous. But new findings are bringing us closer to putting an end to this nauseating part of pregnancy. A large recent study further supports the idea that the hormone responsible for pregnancy sickness, GDF15, may also be the key to preventing it.Finally, Clare and Rowan discuss the growing need for AI to self-identify as non-human, with Chatbots becoming increasingly difficult to distinguish from people…On the pod are Rowan Hooper, Clare Wilson, Alice Klein, Michael Le Page and James Dinneen. To read more about the stories, subscribe at newscientist.com/podcasts. Hosted on Acast. See acast.com/privacy for more information.