Andaman Worm Snake

The Andaman worm snake, Gerrhopilus andamanensis, is a harmless, burrowing blind snake belonging to the family Gerrhopilidae. Endemic to the Andaman Islands in the Bay of Bengal, it represents a distinctive component of the archipelago’s insular herpetofauna. Historically described under the genus Typhlops, the species was reassigned to Gerrhopilus following phylogenetic studies that clarified evolutionary relationships among blind snakes.

Geographic Range

Gerrhopilus andamanensis is confined to the Andaman Islands, with the original type locality designated simply as “Andaman Islands”. Its distribution is therefore strictly insular, and no populations are known from the neighbouring Nicobar Islands or the Indian mainland. The species’ subterranean habits mean that it is rarely encountered, and detailed locality data remain limited.

Taxonomic Notes

The species was first described in 1871, based on early collections from India and Burma. It appeared under the name Typhlops andamanensis in nineteenth-century catalogues and remained so classified until molecular phylogenetics reshaped the taxonomy of blindsnakes. A major study in 2010 demonstrated deep evolutionary divergences within the blindsnake lineage, leading to the reassignment of Andaman material to Gerrhopilus.
No subspecies are currently recognised, and available material suggests a morphologically conservative species typical of fossorial snakes.

Description and Ecology

As a blind snake, G. andamanensis is elongate, cylindrical, and worm-like, adapted for a burrowing lifestyle. While detailed measurements from modern field studies are scarce, its general characteristics include:

• a smooth, glossy body with uniform scales,
• a reduced or vestigial eye concealed beneath ocular scales,
• a narrow head that merges seamlessly with the neck, facilitating soil penetration.

The species is presumed to feed on small invertebrates, such as ants, termites, and their larvae, behaviour consistent with related blindsnakes. Its fossorial mode of life renders it seldom observed during the day, with most records originating from soil digging, chance encounters, or after rainfall.

Behaviour and Habitat

Gerrhopilus andamanensis inhabits moist soil layers, leaf litter, and rotting logs within forested or semi-forested landscapes of the Andamans. Its behavioural repertoire aligns with other blind snakes:

• secretive and subterranean,
• slow moving but capable of rapid burrowing when disturbed,
• non-venomous and entirely harmless to humans.

Given the Andaman Islands’ tropical climate and rich detrital ecosystems, suitable habitat is widespread, though the species’ exact ecological preferences remain understudied.

Scientific and Biogeographical Significance

The Andaman worm snake is of particular interest to biogeographers and evolutionary biologists studying Gondwanan lineages. Molecular analyses indicate that blindsnakes represent an ancient, widely dispersed group whose evolutionary roots predate the breakup of Gondwana. The presence of Gerrhopilus in the Andamans contributes to understanding patterns of dispersal and isolation in oceanic and continental island systems.
Historical references—from the early descriptions of the 1870s to the British Museum catalogues of the late nineteenth century—provide a baseline for modern taxonomic revisions. Ongoing phylogenetic research continues to refine the evolutionary placement of Gerrhopilidae within the broader squamate tree.