Ankarana Special Reserve

The Ankarana Special Reserve is a protected area located in northern Madagascar.

Established in 1956, this reserve protects a unique landscape known as a massif. The area is a partially vegetated plateau composed of middle Jurassic limestone. This specific rock is approximately 150 million years old. The rugged relief and dense vegetation serve as natural barriers. These features have helped protect the region from human intrusion and exploitation. Today, much of the area is designated as the Ankarana National Park.

The landscape is defined by a process called karst topography. This occurs when rainfall erodes the underlying limestone over long periods. This erosion creates deep gorges and feeds subterranean rivers beneath the surface. In the center of the plateau, seismic activity and rain create ribbons of flowstone. On the western edge, the plateau ends in the "Wall of Ankarana." This is a sheer cliff that rises up to 100 meters. To the south, the limestone breaks into separate spires called tower karst.

In some areas, the erosion is so intense that it reaches the harder base rock. This creates sharp channels and ridges known as tsingy. The Malagasy name for this feature means "where one cannot walk barefoot." The terrain is also littered with basalt boulders. Basalt has also flowed deep into the canyons that dissect the massif. This combination of limestone and basalt creates a complex geological environment. The plateau slopes gently toward the east, creating a varied physical structure.

Exploration of these underground systems began in earnest during the 1960s. A Frenchman named Jean Duflos, who later changed his name to Jean Radofilao, led much of this work. He explored the cave systems and subterranean rivers, often working alone or with visiting speleologists. These explorers mapped around 100 kilometers of cave passages within the massif. The massif contains the longest cave systems in Madagascar. It may even contain the longest cave systems in all of Africa. One notable example is La Grotte d'Andrafiabe, which has many horizontal passages.

Scientific expeditions in the 1980s led to many significant biological discoveries. Researchers found sub-fossil remains of large, extinct lemurs. They also discovered previously undescribed species of blind fish, shrimp, and other invertebrates. In 1986, Phil Chapman and Jean-Elie Randriamasy conducted a study of the local bird population. They recorded 65 different bird species from 32 different families. This represents nearly one third of all bird species that breed in Madagascar.

Many small insect-eating songbirds in the reserve use a unique survival strategy. Species like the paradise flycatcher, sunbird, and bulbul forage together in mixed bands. Within these bands, different species specialize in different parts of the trees. Some birds search tree trunks and branches, while others look under leaves. This behavior likely increases foraging efficiency because each species can catch prey that escaped another.

This group strategy also provides safety. A larger group is more likely to spot approaching predators.

The reserve is a vital refuge for many living mammal species. Significant populations of the crowned lemur and Sanford's brown lemur live here. Other recorded species include the northern sportive lemur, the aye-aye, and the brown mouse lemur. The area also hosts the fat-tailed dwarf lemur and the eastern woolly lemur.

Scientists have also found fossils of extinct species like the indri and the sloth lemur. The presence of both living and extinct species makes Ankarana a critical site for understanding Madagascar's natural history.