Andasibe-Mantadia National Park

The entry into Andasibe is abrupt: the road from Antananarivo descends from high plateau into a valley where the forest closes in from both sides, the canopy rising 30 to 40 metres overhead, every surface covered in moss, ferns and orchids that grow in the constant moisture of a rainforest that receives over 1,700 millimetres of rain per year.

The sound that defines Andasibe is the call of the indri (Indri indri): a haunting, whale-like wail that begins before dawn and echoes across the valley in a pattern that researchers believe functions as territorial advertisement between groups.

The indri is the largest living lemur, with a typical head-body length of about 64 to 74 centimetres and a weight of 6 to 9 kilograms, and its black-and-white pelage and distinctive round ears make it unmistakable in the forest canopy, where it moves by vertical clinging and leaping rather than the quadrupedal walking of smaller lemurs.

The groups move through a home range of approximately 18 to 40 hectares, and visitors on the main walking trails have a reasonable chance of sighting them on most days, particularly in the early morning when the groups are most active and the fog in the valley adds an atmospheric quality to the forest.

Camera traps set in the forest have documented a range of secretive mammals including the short-tailed mongoose, the Madagascan ring-tailed vontsira (a carnivore), and the lesser hedgehog tenrec, which is one of several tenrec species that fill the ecological niches occupied by hedgehogs and shrews in other parts of the world.

The forest also supports RAv Benson's dragon tree (Dracaena perrotii), a spectacular plant with a twisted trunk and terminal crown of sword-shaped leaves that is endemic to this part of eastern Madagascar and can reach heights of 8 to 10 metres, creating a structural layer in the forest that is visually distinct from the surrounding canopy.

Orchids are a particular feature of Andasibe: more than 100 species have been recorded in the park, many of them epiphytic on the upper branches of trees where they receive enough light, and the peak flowering season for many species runs from September to November when the forest is at its most colourful.

The forest is estimated to be over 1,000 years old as a continuous ecosystem, and the soils and hydrology of the Mantadia section in particular have been undisturbed by agriculture for centuries, making this one of the most ecologically intact rainforests remaining in eastern Madagascar.

Walking through the forest at any time of day is a full sensory experience: the moisture on your skin, the smell of decomposing leaf litter, the occasional flash of a birds wing overhead, and the persistent sound of running water from streams that flow throughout the year from the high plateau above.

Andasibe is the most accessible rainforest park from Antananarivo and the most reliable place to see the indri (Indri indri), the largest living lemur, whose haunting territorial calls are one of the most distinctive sounds in African nature.

More than 100 species of orchids and a rich community of endemic birds, reptiles and mammals make this one of the most biodiverse reserves in Madagascar.

The park is well-established for tourism with a network of marked trails and experienced local guides who know the locations of habituated indri groups.