LEVITON, BROWN, & SILER: PHILIPPINE VENOMOUS SNAKES 
475 
The Dangerously Venomous Snakes of the Philippine Archipelago 
M 
Introduction 
To fewer than 33 speeies of dangerously venomous snakes inhabit the Philippine Islands 
I and the surrounding eoastal waters (41, if one ineludes eight sea snakes that have yet to 
be found in Philippine coastal waters but are likely to occur there). Of the possible 41 species, 26 
are sea snakes and except for two, Laticauda colubrina and L. laticaudata, none voluntarily come 
onto land (although some sea snakes may wash ashore during severe weather). The remaining 15 
species are terrestrial living in various habitats on land and in freshwater. Several terrestrial 
species, such as Tropidolaemus [formerly Trimeresurus] subannulatus [formerly wagleri], favor 
arboreal habitats and seldom descend to the ground. All terrestrial species can swim, and some reg¬ 
ularly occur near human habitations, in agricultural areas, and typically around sources of water 
such as flooded rice fields, rivers, and streams. 
Two families of dangerously venomous snakes are represented in the Philippine herpetofauna, 
Elapidae (including sea snakes [subfamilies Hydrophiinae and Laticaudinae]), and Viperidae. A 
number of mildly venomous snakes occur in the archipelago as well, and most are members of the 
highly diverse snake family Colubridae; these include the rear-fanged Asian vine-snakes (Ahaetul- 
la), cat-eyed snakes (Boiga), mock viper (Psammodynastes), and two aquatic and semi-aquatic 
snakes (Enhydris, Cerberus). How dangerous any of these are to humans is still an open matter for 
research. Several of the supposedly non-venomous Asian colubrids have been shown to have toxic 
salivas, and some can be considered mildly, if not dangerously, venomous. Some non-Philippine 
watersnakes (selected species of Tropidonophis and Rhabdophis) have been shown to be life threat¬ 
ening to humans but to date, in the Philippines none of these genera have been shown to be dan¬ 
gerous. What we do know is that we often underestimate the severity of many snakebites of both 
juvenile dangerously venomous and supposedly non-dangerously venomous snakes. Yet, bites of 
just such animals have been implicated in the deaths of several knowledgeable professional her¬ 
petologists, notably Karl Patterson Schmidt who, in 1957 at the age of 67, was bitten by a juvenile 
boomslang (Dispholidus typus), an African rear-fanged snake, and died a day later; in 1965, Fred 
Shannon, M.D., was bitten by Crotalus scutellatus, and a few years later, in 1975, Robert Mertens, 
was bitten by another African rear-fanged snake, Thelotornis eapensis, and both died as a result of 
the bites. And, most recently, in 2001, Joseph Slowinski, at the age of 38, was bitten by a 30 cm 
long juvenile krait, Bungarus wanghaotingi, and 
died within 48 hours. 
At this point we emphasize that extreme care 
should be exercised when handling any snake, even 
those that are supposedly non-venomous. It is not 
always possible to tell the difference between ven¬ 
omous and non-venomous species without careful 
inspection. In the Philippines, for instance, several 
snakes are black with white bandings; among these 
are Lyeodon subcinctus, Calamaria lumbricoidea, 
juveniles of several species of Oxyrhabdion, 
Oligodon, and Chrysopelea, as well as the six 
species of venomous snakes that are referred to the 
genera Hemibungarus and Calliophis. The snakes 
of the first group are non-venomous, the latter two. 
Figure 1 . Looks can be deceiving. A field colleague 
recently picked up and photographed this innocent¬ 
looking snake in the belief it was a non-venomous 
species of Calamaria. It is, in fact, a coral snake, of the 
genus Calliophis. Photo by N. Antoque. 
