A large paleontological assemblage typical of Ailuropoda-Stegodon fauna was discovered in the Cave of the Monk, in northern Thailand. Geological and taphonomic approaches were conducted in order to determine site formation processes. A sedimentological study indicated that the fossiliferous layer resulted from medium-size burrowing animals occupying the cave. Bone surface analysis confirmed that Porcupine was the main, if not exclusive, bone accumulator. A bone accumulation rate was calculated. The assemblage appears to have formed over an average period of one to several tens of thousand of years. This time frame means that the assemblage can not be considered as a homogeneous reference for palaeoenvironmental reconstruction as may have been assumed without the present analysis.