Hydrophis semperi
Encyclopedia
Hydrophis semperi, known in some circles as Garman's sea snake, is a rare sea snake found only in a single lake on the island of Luzon
in the Philippines
. It is noted for being one of two known species of sea snake (and the only one in its family) that is known to be found almost-exclusively in freshwater.
H. semperi is usually classified in the subfamily Hydrophiinae
of the family Elapidae
, although in some classification schemes, it and the rest of the "true" sea snakes are instead grouped in the family Hydrophiidae.
Like all "true" sea snakes, it is a rather heavyset snake, elongated with a small head. It possesses the characteristic flattened, paddle-like tail found in the members of its subfamily. This particular species is considered short in comparison to the rest of the family; adult specimens of H. semperi that have been caught were in the realm of 50 cm to 70 cm in length. The snake is colored much like a typical sea snake, having a dark blue or black body with alternating yellow (sometimes white) bands encircling its body. Like its close relatives, its nostrils are located almost dorsally, with valves that prevent water from entering its nasal (and oral) cavities when the snake is submerged.
This snake is known to be found only in the waters of Lake Taal (formerly known as Lake Bombon) in the province of Batangas
in the Philippines
. The only freshwater sea snake in the country, it lives the entirety of its life within the confines of the lake, feeding and breeding in its slightly acidic waters. The lake itself is a volcanic crater lake
, which was formerly saltwater but gradually lost its salinity after the lake was closed off from the sea by an eruption in the 16th century. It is this unique aspect of the lake's formation and history that led to the evolution of several once-saltwater species, including H. semperi. Thus, this species is relatively young, having been accustomed to freshwater for less than a millennium.
As with "true" sea snakes, H. semperi is piscivorous, feeding primarily on the numerous fish species that are known to dwell in Taal Lake's murky waters. Very little is known about the snake's life history, including its ecology and breeding cycles.
Since so little is known about the species' reproductive habits, there have been virtually no estimates of the snake's population. Like many other species endemic to the lake, it is vulnerable as a species to any anthropogenic effects on the lake's ecosystem, both direct and indirect. Pollution
is always a major issue when it comes to enclosed bodies of water with numerous surrounding human settlements. The numerous commercial establishments, towns and plantations dumping chemicals and sewage into the lake, combined with the dense population of fish farms in the lake's waters may yet have an adverse effect on the health of the species as a whole. In addition, while the snake itself has no commercial value and is not harvested, it suffers from the typical human stigma
that is often attributed to snakes. Fishermen that frequently encounter the docile snakes have been known to kill them simply because of what they are.
The snake was named for Carl Semper
, a German ecologist who discovered the species in the mid-19th century. It is also sometimes referred to as Garman's sea snake. Locally, the snake is known as duhol.
Luzon
Luzon is the largest island in the Philippines. It is located in the northernmost region of the archipelago, and is also the name for one of the three primary island groups in the country centered on the Island of Luzon...
in the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
. It is noted for being one of two known species of sea snake (and the only one in its family) that is known to be found almost-exclusively in freshwater.
H. semperi is usually classified in the subfamily Hydrophiinae
Hydrophiinae
Hydrophiinae, also known as sea snakes, is a group of venomous elapid snakes that inhabit marine environments for most or all of their lives. Though they evolved from terrestrial ancestors, most are extensively adapted to a fully aquatic life and are unable to move on land, except for the genus...
of the family Elapidae
Elapidae
Elapidae is a family of venomous snakes found in tropical and subtropical regions around the world, terrestrially in Asia, Australia, Africa, North America and South America and aquatically in the Pacific and Indian Oceans...
, although in some classification schemes, it and the rest of the "true" sea snakes are instead grouped in the family Hydrophiidae.
Like all "true" sea snakes, it is a rather heavyset snake, elongated with a small head. It possesses the characteristic flattened, paddle-like tail found in the members of its subfamily. This particular species is considered short in comparison to the rest of the family; adult specimens of H. semperi that have been caught were in the realm of 50 cm to 70 cm in length. The snake is colored much like a typical sea snake, having a dark blue or black body with alternating yellow (sometimes white) bands encircling its body. Like its close relatives, its nostrils are located almost dorsally, with valves that prevent water from entering its nasal (and oral) cavities when the snake is submerged.
This snake is known to be found only in the waters of Lake Taal (formerly known as Lake Bombon) in the province of Batangas
Batangas
Batangas is a first class province of the Philippines located on the southwestern part of Luzon in the CALABARZON region. Its capital is Batangas City and it is bordered by the provinces of Cavite and Laguna to the north and Quezon to the east. Across the Verde Island Passages to the south is the...
in the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
. The only freshwater sea snake in the country, it lives the entirety of its life within the confines of the lake, feeding and breeding in its slightly acidic waters. The lake itself is a volcanic crater lake
Crater lake
A crater lake is a lake that forms in a volcanic crater or caldera, such as a maar; less commonly and with lower association to the term a lake may form in an impact crater caused by a meteorite. Sometimes lakes which form inside calderas are called caldera lakes, but often this distinction is not...
, which was formerly saltwater but gradually lost its salinity after the lake was closed off from the sea by an eruption in the 16th century. It is this unique aspect of the lake's formation and history that led to the evolution of several once-saltwater species, including H. semperi. Thus, this species is relatively young, having been accustomed to freshwater for less than a millennium.
As with "true" sea snakes, H. semperi is piscivorous, feeding primarily on the numerous fish species that are known to dwell in Taal Lake's murky waters. Very little is known about the snake's life history, including its ecology and breeding cycles.
Since so little is known about the species' reproductive habits, there have been virtually no estimates of the snake's population. Like many other species endemic to the lake, it is vulnerable as a species to any anthropogenic effects on the lake's ecosystem, both direct and indirect. Pollution
Pollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
is always a major issue when it comes to enclosed bodies of water with numerous surrounding human settlements. The numerous commercial establishments, towns and plantations dumping chemicals and sewage into the lake, combined with the dense population of fish farms in the lake's waters may yet have an adverse effect on the health of the species as a whole. In addition, while the snake itself has no commercial value and is not harvested, it suffers from the typical human stigma
Original sin
Original sin is, according to a Christian theological doctrine, humanity's state of sin resulting from the Fall of Man. This condition has been characterized in many ways, ranging from something as insignificant as a slight deficiency, or a tendency toward sin yet without collective guilt, referred...
that is often attributed to snakes. Fishermen that frequently encounter the docile snakes have been known to kill them simply because of what they are.
The snake was named for Carl Semper
Carl Semper
Carl Gottfried Semper was a German ethnologist and animal ecologist. He achieved a Ph.D. in zoology from the University of Würzburg in 1856. He traveled to the Philippines and Palau two years later, staying in the region until 1865 in association with Museum Godeffroy...
, a German ecologist who discovered the species in the mid-19th century. It is also sometimes referred to as Garman's sea snake. Locally, the snake is known as duhol.