The Himalayas contain many unique and ancient cultures. Recently, a team of researchers and mountaineers led by archaeologist Dr. Mark Aldenderfer began unraveling mysteries surrounding peoples who lived thousands of years ago in the caves of Nepal's Upper Mustang region.

Aldenderfer led a 20-day expedition to the Upper Mustang to explore mysterious communal graves discovered in the 1990s. The skeletons and burial artifacts were found in caves on the sides of cliffs. To identify possible burial sites, Aldenderfer and his team, including bioarchaeologist Dr. Jackie Eng and seven-time Everest climber Pete Athans, combed the region for deep caves on the brink of collapse. The bones that Aldenderfer's team collected, thought to be the mysterious Membrak people, were then cleaned, pieced together, and analyzed.

For Dr. Eng, when an ancient communal grave is uncovered, her first job is to identify the number of individuals in the burial context. She does this by counting the number of left femurs. Bones hold important information about an individual's age, sex, and lifestyle. A fracture can be evidence of violence or of environmental peril, for example. From analyzing the bones, Eng can create a sort of character narrative for each individual, illustrating what life might have been like thousands of years ago in this high mountain environment.

For Aldenderfer, finding ancient human bones is exciting, but what he's really after are teeth and what he can learn from them. Most of the critical information held in the human body can be found in a single molar: analysis of dentine determines ancient DNA, while radiocarbon dating, and carbon and nitrogen isotopes in tooth enamel provide information about diet during childhood. Remarkably, strontium isotope analysis of tooth enamel, which forms during the neonatal period, can now tell us the birthplace of each individual.

Transcript

- [Narrator] Everyone it seems, has a stake in the remains. Most important for Mark are the teeth. The first skull, toothless.

- [Mark] There's a little tooth fragment in there.

- [Speaker] Oh, well, yeah, yeah,

- [Narrator] Jackie assembles the bones anatomically, trying to puzzle together complete people to get an accurate count.

- So here's the parietal, occipital. So like this part, the skull, here's the face. So this goes like this. So that's one individual.

- Here comes the other. These people are really pros at losing their teeth. There's just no teeth left whatsoever, but the bone has all been reabsorbed and it's all closed again. All those teeth on top are gone. Oh boy.

- [Jackie] Gummy.

- Yep, gummy. Where's my DNA?

- [Jackie] So at least three individuals. So you've got at least two different adults, based on the duplicates of the scapula, duplicates of the pelvis, and then one juvenile. So at least three individuals within this hall.

- [Narrator] The bones for Jackie are like reading the personal diaries of the deceased.

- They're basically the only physical evidence of these people. They're recording the history of these peoples in terms of the diseases they survived, the fractures that they might have had earlier in life, the types of food they were eating, everything that they experienced in life. It kind of gets recorded onto their skeletal structure, and these trying to adapt to that particular time in history.

- [Narrator] Finally, for Mark, the promise of viable DNA.

- More teeth, okay, score. I'm very happy to see that there's a tooth and this individual hasn't lost all of his teeth yet. The best part of it all, and the most exciting part is that yes, the cave tombs had human remains, and yes, they have the right kind of material for us to extract the DNA, human teeth. And so this is an integral part of the project that we're trying to develop here. By getting those teeth, it's gonna really begin to help us understand who these people are and where they came from and when that all happened.

- [Narrator] Archeologists also look for exceptional stories written onto bones.

- The skull is intact except there's a large piece missing, and you've got these radial, radial fractures--

- [Jackie] Radial fractures.

- Coming away from that spot. It's quite curious.

- It looks like it could be a bash, and then radiating fracture.

- That's what I was thinking is that the person might have been hit in the head, by something very hard.

- [Speaker] Yes.

- [Narrator] Bone fractures could be evidence of violence in the culture, or confirmation that because of rock falling, this is a perilous place to live.

Transcripción

- [Narrador] Parece que todos tienen interés en los restos. Lo más importante para Mark son los dientes. El primer cráneo, sin dientes.

- [Mark] Hay un pequeño fragmento de diente ahí.

- [Orador] Claro sí, sí.

- [Narrador] Jackie ensambla los huesos anatómicamente, trata de armar personas completas para obtener un conteo preciso.

- Aquí está el parietal, occipital. Está esta parte, el cráneo, aquí está la cara. Esto va así. Es un individuo.

- Aquí está el otro. Estas personas parecen expertas en perder sus dientes. No queda ningún diente, pero el hueso ha sido reabsorbido y todo está cerrado de nuevo. Todos esos dientes de arriba no están. Vaya.

- [Jackie] Desdentado.

- Sí, desdentado. ¿Dónde está el ADN?

- [Jackie] Al menos tres individuos. Hay al menos dos adultos diferentes, con base en los duplicados de la escápula, duplicados de la pelvis, y una persona joven. Hay al menos tres individuos dentro de este salón.

- [Narrador] Los huesos de Jackie son como leer los diarios personales de los fallecidos.

- Básicamente, son la única evidencia física de estas personas. Registran la historia de estas personas en términos de las enfermedades que sobrevivieron, las fracturas que pudieron haber tenido en vida, los tipos de alimentos que comían, todo lo que experimentaron en la vida. De alguna manera, se registra en su estructura ósea, e intentan adaptarse a ese momento particular en la historia.

- [Narrador] Finalmente, para Mark, la promesa de ADN viable

- Más dientes, bien, genial. Me alegra mucho ver que hay un diente y que este individuo no ha perdido todos sus dientes aún. La mejor parte de todo, y la más emocionante es que sí, las tumbas en la cueva tenían restos humanos, y sí, tienen el tipo correcto de material para que podamos extraer el ADN, dientes humanos. Esta es una parte integral del proyecto que estamos tratando de desarrollar. Obtener esos dientes nos ayudará a entender quiénes son estas personas, de dónde vinieron y cuándo sucedió todo eso.

- [Narrador] Los arqueólogos también buscan historias excepcionales escritas en los huesos.

- El cráneo está intacto excepto por una gran pieza, y están estas fracturas radiales, fracturas radiales...

- [Jackie] Fracturas radiales.

- Que se alejan de ese punto. Es bastante curioso.

- Parece que podría ser un golpe, y luego una fractura radial.

- Es lo que estaba pensando, que la persona podría haber sido golpeada en la cabeza por algo muy duro.

- [Orador] Sí.

- [Narrador] Las fracturas óseas podrían ser evidencia de violencia en la cultura, o confirmación de que debido a la caída de rocas, este es un lugar peligroso para vivir.