Philippine E-Journals

Notes on Mangrove Snake Boiga dendrophila multicincta (Boulenger, 1896) in Iwahig River, Puerto Princesa City

Roger G. Dolorosa

 

Abstract:

The genus Boiga is composed of about 20-30 species (Rodda et al. 1999) and widespread throughout low elevation and coastal habitats of the Philippines and other Asian countries. A sub-species, Boiga dendrophila divergens had been reported from the northeastern Luzon including the Babuyan Islands (see Brown et al. 2013). A Palawan endemic sub-species Boiga dendrophila multicincta is locally called ‘binturan’ (Leviton 1970). The species is commonly encountered in a semi-disturbed river in Iwahig, Puerto Princesa City, Palawan, Philippines. The one shown in the photo (~2m long) was spotted resting on branches of the mangrove tree Scyphiphora hydrophyllacea along the bank of Iwahig River, Puerto Princesa City (Figure 1).  Two of the nine transect lines (intended for molluscs) had one mangrove snake at the start; several individuals were subsequently noted resting on branches of mangrove trees along the river banks, suggesting an unusually high population density. The same species is abundant in a semi-disturbed mangrove forest in Sitio Bunuangin, Port Barton, San Vicente (MPG Soniega, pers. comm.) and in a pristine mangrove forest in Puerto Princesa Underground River – one of the New Seven Wonders of Nature. The snake is feared for its tendency to chase intruders (people) once hurt. At night, it feeds on a variety of small vertebrates including birds, frogs, snakes and fishes (Minton & Dunson 1978; Savidge 1988). Boiga spp. are both important in the pharmaceutical industry (e.g. Lumsden et al. 2005; Mackessy et al. 2006) and pet trade (Shepherd et al. 2004; Mendizabal 2011).  The mangrove snake is one of the many reptilian fauna in Palawan - the so-called “Philippines’ Last Frontier”. However, mangrove snake and other reptiles are illegally traded from Palawan. In 2011, 25 snakes, including 15 mangrove snakes, 9 vipers and a spitting cobra were seized by officials of the Palawan Conservation for Sustainable Development (PCSD) in El Nido, Palawan (Mendizabal 2011). While record of confiscation is limited, the magnitude of trade could  be  far  higher  than  this.  In   addition,   the   seemingly   unabated widespread habitat degradation in Palawan (Ramirez 2012; Tesorio 2013) could also threaten the existence of these species. Population survey and trade along with education and information campaign, and habitat protection and restoration could help conserve the populations of these mangrove snakes