Extreme Cave Diving
"Extreme Cave Diving" follows a fearless team of scientists as they venture into blue holes—underwater caves that formed during the last ice age, when sea level was nearly 400 feet below what it is today. These caves, little-known treasures of the Bahamas, are one of Earth's least explored and perhaps most dangerous frontiers. The interdisciplinary team of biologists, climatologists, and anthropologists, led by renowned cave explorer Kenny Broad, discover intriguing evidence of the earliest human inhabitants of the islands, find animals seen nowhere else on Earth, and recover a remarkable record of the planet's climate. The stakes are high as the scientists swim hundreds of feet through narrow, dark passages that have trapped and killed divers in the past, but the scientific payoff is considerable.
00:26:22 So what happened?
00:26:24 STEADMAN: The bones I've picked out so far, every one of them represents a species of bird that isn't on the island anymore.
00:26:30 Based on just this tiny sample, it looks like we're on our way to documenting a pretty drastic change.
00:26:39 NARRATOR: About a thousand years ago, most of these animals mysteriously disappeared.
00:26:45 A fossil trail extending back roughly 12,000 years suddenly goes cold.
00:26:53 What killed these animals off?
00:27:01 In 1492, when Christopher Columbus first made landfall in this hemisphere, it was in the Bahamas.
00:27:10 He encountered a people called the Lucayans.
00:27:16 The Lucayans descended from people that came from South America around 800 B.C.
00:27:22 and slowly migrated to the Bahamas.
00:27:28 At the time, Columbus wrote almost nothing about their rituals or traditions.
00:27:35 What little we know today suggests that they thought blue holes were sacred.
00:27:47 They believed caves were the birthplace of humankind and that when someone died, they should be put back inside.
00:28:06 In the early 1990s, in a blue hole called Sanctuary, on Andros Island, a diver found human remains that may have been related to the Lucayans' ritual burial.
00:28:20 Following up on that lead, the team will search for more remains, beginning at Sanctuary.
00:28:27 They'll try to determine if there's a link between the Lucayans and the animal die-off that occurred about a thousand years ago.
The episode includes a recreated scene with the Europeans and Indians inspecting each other. No problem there.
Let's skip over the fact that the divers were desecrating what sounds like a sacred burial site. Perhaps the Lucayans don't have any descendants left, but if they did, were they consulted about this dive?
The scientists don't quite say it, but the theory they're exploring is that the Lucayans killed all the species native to the Bahamas. It's a small-scale version of the megafauna extinction theory. I.e., that Indians weren't the environmental stewards everyone thinks they are. That they ruthlessly killed everything in sight like stereotypical savages.
The results aren't in
And the findings from the dive?
00:35:15 But critical questions remain: Are they connected to the catastrophic die-off of animals here?
00:35:23 And could these skulls belong to the Lucayans, the same people Columbus wrote about?
00:35:32 Pateman identifies a deformity in the skulls that seems to confirm their identity.
00:35:40 PATEMAN: When they were children, the Lucayans bound the foreheads and the backs with boards and then wrapped them, and so that would create this, what you see here, this conical shape.
00:35:51 NARRATOR: It's a characteristic found only in cultures like that of the Lucayans.
00:35:57 And when the skulls are radio carbon-dated, there's an even bigger revelation.
00:36:06 The skulls found in the blue holes date from about 800 years ago.
00:36:11 By then, the Lucayans were already settling in the Bahamas and having an impact.
00:36:20 And the animal die-off that David Steadman identified started about a thousand years ago.
00:36:27 The dates are close enough that it's likely there's a link between the Lucayans and the deaths of the animals here.
00:36:37 We have great fossils from about 12,000 years ago up to about when the first people arrived.
00:36:45 So when people show up, along with non-native mammals that they bring--whether it's rats, cats, dogs, pigs, things like that--these island species are very poorly adapted to these new super predators.
00:37:01 On islands across the world, the most vulnerable species have been wiped out.
00:37:06 They're extinct.
First, an 800-year-old skull doesn't tell us much about a 1,000-year-old die-off. The scientists shouldn't act as if they've proved anything.
Second, they offer an alternative explanation only at the end. Maybe the Indians didn't wantonly kill the native species, they acknowledge. Maybe they inadvertently killed the native species by bringing domesticated animals to the islands. They couldn't have known this would trigger an ecological disaster. Modern scientists have just begun documenting this phenomenon in recent decades.
Third, they don't consider any other alternatives. Here are a couple:
All in all, Extreme Cave Diving is a solid episode of NOVA. But it's a little lacking in scientific rigor.
For more on the subject, see The 2009 TV Season So Far and TV Shows Featuring Indians.
Below: "The deep, oxygen-free zone of one of the caves preserved an 800-year-old human skull, shedding light on the Lucayan people who inhabited the Bahamas long before Columbus visited." (Jill Heinerth/National Geographic Television)