Ankarana Special Reserve

Ankarana Special Reserve
IUCN category IV (habitat/species management area)
Location of Ankarana Reserve
Location	Northern Madagascar
Nearest city	Antsiranana (Diego Suarez)
Coordinates	13°4′22″S 48°54′53″E / 13.07278°S 48.91472°E / -13.07278; 48.91472Coordinates: 13°4′22″S 48°54′53″E / 13.07278°S 48.91472°E / -13.07278; 48.91472
Area	182 km2 (70 sq mi)
Established	1956
Visitors	approx. 6000 (in 2005)
Governing body	Madagascar National Parks
Website	madagascar%20national%20parks

Ankarana Special Reserve in northern Madagascar was created in 1956. It is a small, partially vegetated plateau composed of 150-million-year-old Middle Jurassic limestone. With an average annual rainfall of about 2,000 millimetres (79 in), the underlying rocks are susceptible to erosion, thereby producing caves and underground rivers—a karst topography. The rugged relief and the dense vegetation have helped protect the region from human intrusion.

The plateau slopes gently to the east, but on the west it ends abrubtly in the "Wall of Ankarana", a sheer cliff that extends 25 kilometres (16 mi) north to south, and rises as high as 280 metres (920 ft). To the south, the limestone mass breaks up into separate spires known as tower karst. In the center of the plateau, seismic activity and eons of rainfall have dissolved the limestone away in deep gorges, and sometimes redeposited it in 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 as tsingy.

The largest sinkhole in the Ankarana karst region, Mangily sinkhole, measures up to 700 meters across and 140 meters deep with a volume of 25 million cubic meters. The area is sacred to the Antankarana people, who have historically taken refuge from encroaching enemy armies in its caves and other natural rock shelters.

Beginning in the 1960s, expatriate Frenchman Jean Duflos (who married locally and changed his name to Jean Radofilao) did a huge amount of exploration of the cave systems and subterranean rivers of the Massif, much of it on his own or with visiting speleologists. A total of about 100 kilometres (62 mi) of cave passages within the massif have been mapped. One of the most accessible caves, La Grotte d'Andrafiabe, alone comprises at least 8.035 kilometres (4.993 mi) of horizonatal passages. Indeed the Massif contains the longest cave systems in Madagascar, and probably in the whole of Africa.

Standing up to leave, I noticed a gentle grunting noise and turned towards it Silhouetted in the entrance, was the unmistakable shape of a Crowned Lemur. She paused, with her long tail held over her body like a furry question mark. Looking away, she grunted softly as if speaking to a friend outside. Then, reassured, the rest of her troop arrived, looked in my direction and, to my amazement, continued on their way down, descending the same familiar climb I had used. They were quite unruffled by my presence.