The Fiji burrowing snake (Ogmodon vitianus) is very distinct from the more widely known Pacific Boa, Candoia bibroni.

Also known as: Fiji Burrowing Snake

Local Names: Bolo

Fiji burrowing snake (Ogmodon vitianus)  map
Fiji burrowing snake (Ogmodon vitianus) map

Description

The Fiji burrowing snake is very distinct from the more widely known Pacific Boa, Candoia bibroni. The Fiji burrowing snake is much smaller, growing up to a maximum snout-vent length of 30 cm. It has a small head which is indistinct from the neck, a short tail, and smooth body scales. The body is a uniform dark brown or mid-brown in colour with lighter sides. The belly is generally pale brown or white blotched with black or brown in colour. Younger snakes can be distinguished by the yellowish mark on the back of the head (see picture). The eyes are small and dark, and do not have a vertical pupil.

Distribution

This snake has only been recorded from Viti Levu from the Wainikoroiluva Valley, the Sigatoka Valley, Naitasiri and the Monasavu area. It may be more widespread throughout the Fiji group, but because of its fossorial and elusive nature, this cannot be confirmed. Within Viti Levu, the burrowing snake has been found within the province of Namosi.

Habitat Ecology and Behaviour

The Fiji burrowing snake, is, as the name suggests, a burrowing snake that lives within loose soil, under leaf litter or beneath termite nests. They have been found as deep as 1 m under rock rubble, in lowland rainforest and inland valleys. More specifically, they are found on valley floors and on low mountain slopes. There have been reports of the snake from plantations, when farmers dig out the soil for planting. They have also been found on the ground surface after heavy rain. Male and female Fiji burrowing snakes attain sexual maturity between 180-200mm SVL. The Fiji burrowing snake is oviparous, meaning that females produce eggs. The eggs are ellipsoidal in shape. The size of hatchlings is unknown as is everything else about the reproductive biology of Fiji’s only endemic snake. They feed on worms, soft-bodies insects and other soil arthropods. The burrowing snake is presumed to be nocturnal, though this has not been confirmed. Even though it produces neurotoxic venom it is very placid and, as reported by Ryan (2000), do not seem to mind being handled. These snakes probably only bite when handled too aggressively.

Threats

It is very probable that this small snake has been under great threat ever since the pig was introduced to Fiji and went feral in the forests. The introduced Indian Mongoose (Herpestes auropunctatus) is also a threat when the snake emerges to the surface and rats may well predate on its eggs. All of these introduced species pose an on-going threat to the survival of this rare endemic snake. Other threats have materialised more recently, much of the land in its known geographic range is being logged, drilled for prospects of mining and converted to agricultural land. The area from which the majority of the burrowing snakes have been collected is within the Wainikoroiluva valley in the province of Namosi, which is within the prospect for the proposed Namosi copper mine. Exploration surveys and drilling for copper deposits have been ongoing within this area since the late 1960s.

Conservation Status

Other then its listing as a ‘Vulnerable’ species in the IUCN list of endangered species, there are no other known efforts to conserve Fiji’s only endemic snake. To survive this snake will require a large area of mixed forest from which pigs, mongooses and other introduced predators are permanently excluded. The impacts of the proposed copper mine surveys and drilling as well as the potential impact of the mining venture on the native and endemic plants and animals that occur within and outside of the Namosi valley will also need to be assessed.Remarks and

Cultural Significance

Other then its listing as a ‘Vulnerable’ species in the IUCN list of endangered species, there are no other known efforts to conserve Fiji’s only endemic snake. To survive this snake will require a large area of mixed forest from which pigs, mongooses and other introduced predators are permanently excluded. The impacts of the proposed copper mine surveys and drilling as well as the potential impact of the mining venture on the native and endemic plants and animals that occur within and outside of the Namosi valley will also need to be assessed.

References

Gorham (1970);
Graeffe (1986);
Keogh et al. (1998);
de Marzan (1987);
Parker and Grandison (1977);
McDowell (1969, 1970);
Morrison (2003);
Ryan (2000);
Zug and Ineich (1993)

Front Page Photo: Paddy Ryan. A juvenile Fiji Burrowing snake, with the distinguishing yellow mark on the back of the head.