In this episode, we’re delving into the topic of extinction. We'll be finding out about some of the animals who are critically endangered, meeting the people trying to rescue them, and exploring species who may be able to make miraculous comebacks. Perhaps one of the most endangered species is the vaquita, a small sea mammal with a population of less than 20. We hear from some extraordinary people weathering threats and tragedies in an attempt to bring these ‘pandas of the ocean’ back from the brink.  According to US Department of Agriculture researcher, Dr Samuel Ramsey, every discovery is built upon a discovery that came before it. Yet some of those discoveries can be found in the most unexpected of places. For Samuel, understanding his father’s health issues provided the key to discovering why honeybee populations are on the decrease. And to finish, we’re asking one of the biggest questions in paleontology: how did birds evolve from dinosaurs? To help us explore this topic, we’ve got the help of Jingmai O’Connor whose work in China has helped shed light on the distant link between the extinct dinosaur and ballooning bird populations. Thank you for listening to another series of the BBC Earth podcast. As ever, we love hearing from you on social media, so do share with us your favourite episode so far or a story that amazed, surprised or moved you… Website: www.bbcearth.com Facebook: www.facebook.com/bbcearth/ Instagram: www.instagram.com/bbcearth/ Twitter: www.twitter.com/bbcearth    See acast.com/privacy for privacy and opt-out information.