The strangest biome of all Madagascar’s ecosystems is the spiny forest, which covers more than 14,000 square kilometres of the country’s southwest and is unique to this corner of the planet. With its multitude of strange forms, including spine-covered tendrils, bulbous stalks and fleshy, cactus-like lobes, the xerophytic (dry-loving) flora of this tangled, alien environment is utterly distinctive – more like the studio set from an early episode of Star Trek than natural vegetation. The forest occurs naturally in this arid landscape, sheltered from the drenching cyclones of eastern Madagascar by the central mountains.
The key plant types in the spiny forest are a brilliant variety of succulents – the euphorbias – as well as the stumpy, triffid-like pachypodiums, the baobabs and dozens of species of a family endemic to Madagascar, the spine-possessed Didiereaceae, which are almost encased in ruthless, hard spines and which can grow to 15m in height.
But the spiny forest isn’t all about the plants: it’s also about the animals that, bizarrely, flourish among them. While the animal life is not as prolific or diverse as the rainforest, this is still a rich and rewarding ecosystem for any amateur naturalist. Iguanas and day geckos, chameleons and tortoises, flightless birds, bats, spiny tenrecs (a family of primitive, shrew-like mammals), all make their home in this dessicated environment, extracting moisture from plants refined by evolution to retain it.
Lemurs are widespread, too, and none seemingly more unsuited to a home amid the thorns than the waif-like Verreaux’s sifaka (Propithecus verreauxi). And yet this cuddly toy of a primate, with its soft inquisitive fingers, seems quite at home clinging vertically to the spine-covered green spears of a giant Allaudia ascendens. What still perplexes primatologists is that the sifakas are able to hurl themselves from spiny trunk to spiny trunk, grasping and landing between the closely set clumps of vicious needles, and are never seen to stab a toe or get a painful surprise in the backside. If you want to witness this compelling phenomenon yourself, the best place to do so is in the Anjapolo part of the Réserve Privée Berenty and at Mangatsiaka in Parc National d’Andohahela.