John Rafferty of Encyclopædia Britannica discusses the Atlantic and Pacific bluefin, two species of tunas that are threatened by overfishing. This is the third part of the Postcards from the 6th Mass Extinction audio series.

John Rafferty of Encyclopædia Britannica discusses the polar bear, a mammal that is among the world's largest carnivores on land, and the threats to its survival. This is the second part of the Postcards from the 6th Mass Extinction audio series.

John Rafferty of Encyclopædia Britannica discusses the challenges of protecting the world's smallest porpoise, the vaquita, from extinction. This is the first part of the Postcards from the 6th Mass Extinction audio series.

John Rafferty of Encyclopædia Britannica and Dr. Barbara Durrant of San Diego Zoo Global discuss the precarious status of the northern white rhinoceros (Ceratotherium simum cottoni) and some of the medical techniques that could be used in its recovery. This is the seventh part of the Postcards from the 6th Mass Extinction audio series.

John Rafferty of Encyclopædia Britannica discusses the challenges that oil palm cultivation poses to orangutans. This is the fifth part of the Postcards from the 6th Mass Extinction audio series.

John Rafferty of Encyclopædia Britannica and Dr. Jonna Mazet of the University of California, Davis, discuss the origins of the coronavirus SARS-CoV-2 and the processes by which emergent viruses spill over from one species to another. This is the ninth part of the Postcards from the 6th Mass Extinction audio series.

John Rafferty of Encyclopædia Britannica discusses two species of monarch butterflies in North America that have declined as a result of habitat loss and the effects of pollution. This is the fourth part of the Postcards from the 6th Mass Extinction audio series.

John Rafferty of Encyclopædia Britannica, Dr. Chelsea Rochman of the University of Toronto, and author Dr. Rebecca Altman examine the chemistry of plastic and plastic pollution and the social history of plastic use. This is the 10th part of the Postcards from the 6th Mass Extinction audio series.

John Rafferty of Encyclopædia Britannica and Dr. Chris Langdon of the University of Miami examine the processes of ocean acidification and coral bleaching. This is the 11th part of the Postcards from the 6th Mass Extinction audio series.

John Rafferty of Encyclopædia Britannica and Dr. Karen Lips of the University of Maryland discuss the chytrid fungus called Batrachochytrium dendrobatidis (Bd) and how it has decimated amphibians worldwide. This is the eighth part of the Postcards from the 6th Mass Extinction audio series.

John Rafferty of Encyclopædia Britannica and Dr. Lucy Hawkes of the University of Exeter discuss sea turtle conservation within the context of sea-level rise and shoreline development. This is the 12th part of the Postcards from the 6th Mass Extinction audio series.

John Rafferty of Encyclopædia Britannica and Dr. Andrew Solow of the Woods Hole Oceanographic Institution discuss the concept of functional extinction. This is the sixth part of the Postcards from the 6th Mass Extinction audio series.