Socotra: The Yemeni Island So Isolated It Evolved Its Own Alien Landscape

There is an island in the Arabian Sea between Yemen and Somalia where a third of all plant life exists nowhere else on Earth. Not a third of a specific genus. A third of every plant species on the island. Over 300 species found in one place and nowhere else in the world. The reptile endemism rate is over 90 percent. The land snail endemism rate is over 90 percent. Whatever has been living on Socotra has been evolving in extraordinary isolation for somewhere between 15 and 20 million years, and the result is a landscape that looks less like something from this planet and more like a set designer’s idea of what an alien world should look like.

The most famous residents are the dragon blood trees. They look like umbrellas turned inside out, or like flying saucers balanced on trunks. Their canopy spreads flat and wide, facing skyward, catching moisture from the mist that rolls across the island’s highland plateaus. When you cut the bark, it bleeds deep crimson. The locals call the resin dragon’s blood. They have used it as medicine, as dye, as incense, for centuries.

How It Got This Way

Socotra is not a volcanic island that pushed up from the ocean floor in relative geological recent times. It is a fragment of an ancient supercontinent. About 20 to 30 million years ago, the African and Arabian landmasses separated, opening the Red Sea and the Gulf of Aden. Socotra was left behind as an isolated chunk, and the plants and animals on it have been evolving separately from anything on the mainland ever since.

The island’s isolation is both geographic and seasonal. Socotra sits about 240 miles east of the Horn of Africa and 250 miles south of the Arabian Peninsula. But the southwest monsoon, which runs from June to September, generates seas rough enough to make the island essentially inaccessible for months at a stretch. This seasonal isolation reinforced the geographic isolation over millions of years, creating conditions where species had almost no contact with outside populations and were free to develop in their own directions.

The result is a catalogue of strangeness. The cucumber tree, Dendrosicyos socotranus, has a massively swollen trunk and branches that look like something a child drew. The desert rose, Adenium obesum socotranum, produces pink flowers from a fat, grey, almost featureless trunk that looks more like a river stone than a plant. The Socotran fig, Dorstenia gigas, grows directly out of limestone cliff faces. The blue baboon tarantula, found only on Socotra, is iridescent. Legless lizards exist there that occur nowhere else. Dozens of endemic crab species live along the coast.

The dragon blood tree, Dracaena cinnabari, can live for a thousand years. The oldest known specimens are hundreds of years old. The plateau forests at Diksam, in the center of the island, contain the largest remaining stands. Walking through them is genuinely disorienting: the flat-topped canopy, the mist, the crimson resin visible on older trunks, the silence. People who have been there consistently report that photographs do not capture it.

The Human History

Socotra has been inhabited for thousands of years, and its isolation shaped its human culture as thoroughly as its biology. The Socotran language is distinct from Arabic and other Semitic languages, part of its own branch that developed in separation from the mainland. The island had no written form of its language until recently. History was carried entirely in oral tradition.

Ancient civilizations knew the island and valued it. Egyptians, Greeks, and Romans all traded for Socotra’s products: frankincense from the Boswellia trees, aloe vera, the crimson dragon’s blood resin, which was traded across the ancient Mediterranean as a medicine and a dye. The Periplus of the Erythraean Sea, a 1st-century Greek navigation text, describes Socotra as an important trading stop. Early Christian communities established themselves there before Islam became the dominant religion. Inscriptions in ancient Greek, Palmyrene, and South Arabian scripts have been found in the island’s cave systems, suggesting the caves functioned as way stations for ancient mariners.

The population today is around 60,000 people, concentrated in the capital Hadiboh on the north coast. The island was a barter-only economy until 1990, which meant it remained almost entirely outside the global commercial system for most of the 20th century. Researchers from the Royal Botanic Garden Edinburgh documented over 60 distinct ways in which the local population used endemic plant species, from medicine to building materials to animal feed. Unlike most island ecosystems, Socotra has lost none of its endemic birds, reptiles, or molluscs in the past century. The low-impact human presence preserved what the isolation created.

The Current Threats

Yemen’s civil war, which began in 2015, complicated everything. Socotra is geographically distant from the mainland conflict, but the political situation brought new pressures. The UAE, which has military interests in the region, sent troops and infrastructure to Socotra beginning in 2018, and the influx of new roads, construction, and connectivity has accelerated development pressures that the island had never faced before.

Two major cyclones, Mekunu in 2018 and Kyarr in 2019, struck the island in quick succession. Cyclones were historically rare in this part of the Indian Ocean. Both caused significant damage to the dragon blood tree forests. Scientists estimate climate change has increased sea surface temperatures in the region enough to generate storms that would not previously have formed. The very conditions that produced Socotra’s endemism, its isolation and its specific climate, are shifting.

The dragon blood tree faces specific long-term pressure from a gradually drying climate. The trees depend on the mist and cloud cover of the highland plateaus for moisture. Studies have predicted that available habitat for the species could decline by 45 percent by 2080 if current climate trends continue. Trees that can live a thousand years are not being replaced fast enough by young seedlings in the drying conditions.

UNESCO has listed Socotra as a World Heritage Site since 2008 and designated it a site of outstanding universal value for biodiversity. The designation has not resolved the conservation challenges, because those challenges are not primarily about policy. They are about a global climate system and a regional conflict that exist at scales no island administration can manage.