Over 1000 terrestrial animal species

34 reptile species of which 90% are endemic

More marine diversity than the entire red sea

Come meet socotra's fascinating fauna

Though Socotra’s flora may be more iconic and well known around the world, the archipelago is also home to a rich diversity of fascinating fauna, many species of which are found nowhere else. Nonetheless, populations of many Socotri animal species are diminishing rapidly some before even being documented. Zoologists and evolutionary biologists believe that Socotra’s current fauna represents a fraction of what currently existed. This is supported by historical texts such as the 1st century CE Periplus of the Erythrean Sea, which states that Socotra once hosted crocodiles and large lizards, both of which do not reside on the island any longer.

In total, over 2500 species of animal have been recorded in Socotra, with this number continuously growing. Of these, roughly ~30% of butterfly species, ~90% of reptiles and ~95-100% of land snails and cave crustaceans are endemic (UNESCO, 2006 & Wranik, 2011). Though enough is already known to confidently deduce the importance of Socotri animal diversity and its conservation, scientists agree that there is still lots to be discovered about this diversity, and particularly the species the live in the archipelago’s extensive cave systems.

Recent studies have shed light on the taxonomic groups of importance on Socotra. Of these, reptiles, birds, insects, arachnids and myriapods have shown to be the taxa with highest levels of endemism, and thus those of greatest conservation importance. Table 5 below gives an overview of the species present in each of these taxa in Socotra’s marine and terrestrial ecosystems. It is worth mentioning that since this table was published in 2006, numerous other species have been documented.

Reptiles

Socotra is home to 34 species of reptile, 4 marine and 30 terrestrial. Of the 30 terrestrial species, an astonishing 27 (90%) are endemic. The most diverse taxonomic group of reptiles on Socotra are the geckos (Gekkonidae) with 18 species, of which 15 are endemic. Otherwise, a charismatic and endemic species often encountered blending-in unassumingly with the trees is the Socotra chameleon (Chamaleo monachus). Socotra is also home to 7 species of snake, of which 5 are elusive blind snakes that reside almost completely underground. The remaining 2, Ditypophis vivax and Hemerophis socotrae, are colorful colubrids, or rear-fanged snakes, that are not harmfully venomous to humans. In addition, 4 different sea-turtle species have been recorded on Socotra, including the world’s largest species of sea-turtle, the vulnerable Leatherback sea-turtle (Dermochelys coriacea) that regularly nests on Socotra’s shores.

Birds

Socotra has a sizable bird diversity estimated at 182 species, of which 41 are breeding residents, 88 are passage migrants and 53 are vagrants (UNESCO, 2006). Of Socotra’s resident bird species, the following 10 are currently described as endemic:

-Socotra sunbird (Chalcomitra balfouri)

-Socotra scops owl (Otus socotranus)

-Socotra sparrow (Passer insularis)

-Socotra cisticola (Cisticola haesitatus)

-Socotra buzzard (Buteo socotraensiss)

-Socotra starling (Onychognathus frater)

-Socotra golden-winged grosbeak (Rhynchostruthus socotranus)

-Socotra warbler (Incana incana)

-Abd al Kuri sparrow (Passer hemileucus)

Invertebrates

Though some may consider them not as charismatic as Socotra’s vertebrate fauna, Socotra’s invertebrates are the archipelago’s most abundant and diverse taxa, and that with the highest levels of endemism. In addition, Socotra’s invertebrate taxa are largely understudied allowing for the likelihood that even more (endemic) species are yet to be documented. Often, the most visible of these invertebrate taxa are Socotra’s 100 or so species of land snail, all of which are currently considered endemic (Wranik, 2011). In addition to the 600 or so insect species present on Socotra, another fairly well represented and fascinating taxa are the arachnids, composed of 59 species of spider, 3 amblypygids and 1 harvestman. The largest of these arachnids are the endemic Socotra blue baboon spider (Monocentropus balfouri) and the Orb weaver (Nephila sumptuosa). While the prior is more elusive, the latter can often be encountered while walking through the highlands of the Socotra island (Hula & Niedobovà, 2012).

The archipelago also acts as breeding ground for a series of other species that are not endemic but that are considered endangered on the global scale. The most easily visible of these, and likely the most visible bird species on the archipelago, the Egyptian vulture (Neophron percnopterus percnopterus) is globally endangered and Socotra likely acts as one of the densest breeding grounds for this species on earth.