Much of the insect life remains unclassified. One recurring characteristic among the known species is reduced wing size, a common trait of island species, developed in order to keep the insects from being blown away by heavy winds. There are 60 species of butterflies.
Socotra also has its share of arachnids, whose most remarkable species is the Blue Baboon Spider Monocentropus balfouri,
including several species of scorpion.
These are at least two types of freshwater crab: Potamon socotransis, and Socotra pseudocardisoma, as well as a large land crab Cardisoma carnifex. The last can be found near mangroves and palm where they dig their burrow.