Complete or near-complete skeletons are rare precisely because the conditions for preservation are difficult to achieve and maintain.

Cave environments offer specific advantages.

Sediment accumulation inside caves tends to be more stable than in open-air settings.

Temperature fluctuates less dramatically.

Moisture, if not excessive, can be moderated by the cave environment.

And the potential for deliberate burial — placing a body in a depression and covering it with sediment — provides additional physical protection against scattering.

At Shanidar, the sequence of sediment deposition inside the cave has been continuous for hundreds of thousands of years.

Neanderthal remains appear in what archaeologists call the Mousterian layers — the geological and cultural strata associated with Neanderthal occupation.