Episode 505: Three Animal Mysteries

Further reading: Scientists solve a shark murder mystery Stone Age Animal Urine Could Solve a Mystery about Technological Development South African rock art possibly inspired by long-extinct species The porbeagle shark [photo by Andy Murch, taken from this site]: Dicynodont fossils and their possible art interpretation by the San people: Show transcript: Welcome to Strange Animals Podcast. I’m your host, Kate Shaw. It’s finally monster month, and I’m looking forward to sharing lots of fun mystery animals and animal mysteries over the next four weeks. Our first mystery is from an article titled “Scientists solve a shark murder mystery.” The word solve is doing a lot of heavy lifting in this case, but let’s find out what happened to the shark. The shark in question was a porbeagle shark, a type of mackerel shark that can grow as much as 12 feet long, or over 3.5 meters, and is gray and white in color. It lives in cold water in the North Atlantic and around Antarctica, and it eats fish and cephalopods like squid. It hardly ever bothers people although people like to eat it, and in some regions it’s been so overfished that the species is listed as endangered. The porbeagle is especially unusual because it’s able to thermoregulate to some degree, like the basking shark and some other sharks that we talked about in episode 353, about warm-blooded fish. The porbeagle is actually really good at keeping its brain, eyes, and internal organs warm, which is why it’s so successful in cold water. It can live to be at least 65 years old. There’s still a lot we don’t know about the porbeagle, including where exactly it lives and how far it migrates throughout the year. A team of scientists has been tagging porbeagle sharks with little transmitters, like shark Air Tags, to find out where the sharks travel and other information, like how deeply they dive and what the water temperature is. The transmitter is attached to a shark’s fin and is designed to stay in place for a year, then detach and transmit all the information it’s gathered as soon as it floats to the water’s surface. In October 2020, the scientists captured an 8-foot, or 2.5 meter, female porbeagle and fitted her with a transmitter before releasing her again. They were especially happy to see that she was pregnant, partly because the porbeagle is endangered and reproduces slowly, partly because they were interested to find out where a pregnant shark traveled. About six months later, in April 2021, the tag began to transmit its information. It was too early for it to have detached on its own, but sometimes something happens to a tag and it ends up removed from the shark before it’s scheduled to. The team’s lead scientist, Brooke Anderson, examined the transmitter’s information and knew something weird had happened to the shark. Everything seemed normal until about a week before the tag began to transmit, when the tag indicated a slight but steady increase in the temperature of its surroundings, even though it was still deep underwater. Anderson suspected that the shark had been killed and eaten at that point, and the tag ended up inside the body of another ani