Ghosts

BBC Earth Podcast

The episode explores the concept of 'ghosts' within the natural world, ranging from ancient fossils to elusive living species and extinct so

Key takeaways

• Fossils like trilobites and mollusks act as biological ghosts, preserving life from millions of years ago.
• The Cradle of Humankind in South Africa is a vital site for studying human evolution through Australopithecus fossils.
• Renata Leite Pitman successfully tracked and rewilded a short-eared dog known as the 'ghost dog' in Peru.
• Singletons are species, such as the giant glow spot cockroach, known to science from only one physical specimen.
• Ecologist Dan Flew uses specialized frequency equipment to track rare bats like the Lesser Horseshoe bat at night.

Main topics

• Fossils and ancient marine life
• Human evolution in South Africa
• The elusive Peruvian ghost dog

Notable quotes

A fossil is the remains of ancient life reaching through time to have an effect in the land of the living.

Conclusion

The episode highlights the profound mystery and fragility of biodivers

Transcript preview

Speaker 4 (0:00) Have you ever been ghost hunting? I have. But this wasn't at night in an old abandoned house using an electromagnetic field detector and a Ouija board. No, no, no. This was the middle of the afternoon, and I was pulled over on the side of a highway just outside of Pittsburgh, Pennsylvania. Speaker 4 (0:31) I wasn't here looking for lingering spirits of the dearly departed, but instead for real ghosts. Fossils. The preserved remains of ancient animals that lived right here in my part of the world, back when it was an ocean floor millions of years ago. I stood looking at the dark stone of the foot of the cliffside. I wedged my chisel into the sedimentary rock, and after landing a few hits with my hammer, I pried away the pieces of shale and limestone, and took a look inside. The first ghost I found? The coiled shell of an ancient mollusk. Speaker 4 (1:25) Before fossilization, this would have been maybe something like a sea snail and could have lived over 300 million years ago. Next, the remains of a crinoid, this strange marine animal that, when it was alive, would have looked like a plant with long, feathered arms sticking out the top. Speaker 4 (1:48) And finally, the most impressive ghost of them all. Part of a trilobite, an ancient marine arthropod. If it were around today, it might remind us of a scuttling crustacean with its hard outer shell and many little legs. All in all, it was a pretty successful ghost hunting trip. Speaker 4 (2:17) Whoever says ghosts are hard to find, they're wrong. You just have to know where to look. I'm Sebastian Echeverri. And Speaker 6 (2:38) I'm Rutendo Shackleton. And Speaker 4 (2:40) this is the BBC Earth Podcast. Speaker 6 (2:52) This episode is all about ghosts. We'll uncover the mysteries of some Peruvian ghost dogs. We'll visit a cemetery to observe some creatures of the night. We'll journey to Svalbard, one of the world's most desolate places. And we'll listen to some extinct voices which have been lost from our natural world. Speaker 6 (3:19) You know, it's kind of weird to think of fossils as ghosts because the word ghost likely conjures up images of see-through, creepy kind of poltergeists that you see in a ghost film, which, by the way, I do not enjoy at all. But, you know, a ghost is exactly what a fossil is, right? Speaker 4 (3:42) Fossils totally have ghost v- vibes. A fossil can be a lot of things, but basically it's the preserved evidence of life that was once here and living. That can be anything from the actual body that's left behind when an organism dies in just the right way in just the right place, or something that left a fleeting impression. A fossil is the remains of ancient life. reaching through time to have an effect in the land of the living. Totally ghostly. I Speaker 6 (4:17) actually remember when I was in my last year of high school in South Africa, my class had a field trip to visit the Cradle of Humankind, which is a UNESCO World Heritage Site, and it's home to the largest concentration of human ancestral remains on the planet. In fact, it is one of the first places where Australopithecus fossils were found. And Australopithecus is one of the ancient humans that started to walk upright like us and also started to use tools as well. Speaker 4 (4:52) Oh, that is fascinating. Such a cool fossil in our history. Do you know what makes the cradle of humankind so special? Why have we found so many human fossils there? Speaker 6 (5:04) So the area has... network of caves called the Sterkfontein Caves. And so what's thought is that, you know, these early humans may have accidentally fallen into the cave, or maybe a flood may have carried the remains into the cave, or some thoughts are that they would bury their dead there. And The cave has the right type of minerals and rock to be able to preserve and fossilize the remains. Oh, Speaker 4 (5:32) that is so cool. The right place, the right time to preserve this part of our evolution. But yeah, that's the thing about fossils. One of the reasons they're so fascinating and mysterious is that they're so rare. You never know when you're going to find that one incredible specimen or what answers it might hold if you do. Speaker 6 (5:52) And mystery plays a huge part in our understanding of the natural world too, right? Scientists often hear ghostly stories and folklore from communities about elusive species that have existed for years, but that so far science has not been able to trace or study. Renata Leite-Pittman heard tales of some mysterious ghost dogs in Peru. She made it her mission to try and find Speaker 2 (6:20) one. Speaker 2 (6:22) My ex-boss started talking about his 30 years research in the Peruvian Amazon. And he started to describe that other researchers saw this ghost dog. Speaker 2 (6:39) The short Speaker 6 (6:39) -eared dog, or ghost dog, is an elusive canine who is rarely seen, and at this point was completely unresearched. Speaker 2 (6:48) And when I heard that, I said, that's impossible. Nobody sees this dog. They must be wrong. Speaker 6 (6:55) Renata wanted to investigate these potential sightings further, so she booked a ticket to Peru. Speaker 2 (7:02) It was a long trip because you need to fly to the capital of Peru, Lima, and then take another flight, then take lots of boats. And after three days, I was in this place, one of the most isolated national parks in Peru. As soon as I arrived, I see tracks of short-eared dogs everywhere. Speaker 2 (7:30) I made myself box traps from wood boards. I got like a different array of baits, you know, from banana, you know, meat and different things that could attract to the dog. And after a month, I didn't catch anything. I was totally frustrated. Speaker 6 (7:53) A month might sound like a long time, but it was just the start for Renata. She searched in the forest for two years without finding anything but tracks and droppings. Renata decided it was time to change location with hopes that she might finally be able to meet a ghost dog. And it was the right move. Speaker 2 (8:18) Well, the first one we caught using bananas, I was with two of my favorite field assistants, and I remember him saying, El perro! El perro! In his entire life, he saw only once, and he's a very good field guide in Peru, so he was completely amazed. Speaker 2 (8:44) The ghost dog looks like a fox. It has like a very bushy tail. The color is brownish chocolate with a very funny nose, pointed nose. We deploy a radio collar on the animal to be able to track it. And then we let it go. Speaker 2 (9:09) After this we caught two short-eared dogs. One was a mother and one was a baby. And this was the only time we followed more than one at the same time. Speaker 2 (9:23) After three days, the mother disappeared. The baby stayed in this area, like it started to move around the tree. When we got in there, we saw a four meters long boa constrictor. And the animal was inside of the belly of the boa constrictor. That's the life of the ghost dog. So that's the reason they are ghosts. You know, they have predators. Speaker 6 (9:50) During her many years in the Peruvian Amazon, Renata did study and track some wild ghost dogs. But her most important breakthrough came just as she was about to Speaker 2 (10:02) go home. Speaker 6 (10:04) When Speaker