[1] With an average annual rainfall of about 2,000 millimetres (79 in),[1] the underlying rocks have been eroded to produce caves and feed subterranean rivers—a karst topography.

The plateau slopes gently to the east, but on the west it ends abruptly in the "Wall of Ankarana", a sheer cliff that extends 25 kilometres (16 mi) north to south, and rises up to 280 metres (920 ft).

In the center of the plateau, seismic activity and eons of rainfall have eroded the limestone, forming deep gorges and ribbons of flowstone.

In places where the calcific upper layers have been completely eroded, the harder base rock has been etched into channels and ridges known in Malagasy as tsingy meaning 'where one cannot walk barefoot'.

[8] Expeditions that first began cataloguing the animals and plants of the Special Reserve created around the Ankarana Massif in the 1980s[9] are described in Dr Jane Wilson-Howarth's travel narrative Lemurs of the Lost World[10] and in the scientific press.

[11][12][13][14] Discoveries included unexpected sub-fossil remains of large extinct lemurs[15][16][17][18] and surviving but previously undescribed species of blind fish,[19][20] shrimps[21] and other invertebrates.