False Water Cobra
Encyclopedia
Hydrodynastes gigas is a rear-fanged venomous
colubrid
species
found in South America
. It is alternatively known as the false water cobra and Brazilian Smooth Snake. No subspecies are currently recognized.
as a defensive reaction to make it look larger and more intimidating. However, unlike the true cobra the false water cobra stays in a horizontal position when it hoods, rather than standing in a vertical position. H. gigas also can flatten not only its neck but also lower down the body, which is not possible for a true cobra.
Additionally, the pattern and coloration of Hydrodynastes superficially resemble those of true water cobras (Boulengerina
).
The false water cobra has large eyes with circular pupils allowing good daytime vision. The tongue is black, and of the typical snake fashion.
The background colour of a mature specimen is an olive green or brown, with dark spots and bands covering much of its body. The background coloring and banding generally becomes darker towards the end tail of H. gigas. This colouring gives the false water cobra effective camouflage in its natural rainforest environment. The ventral scales
are yellow or brown, spotted with dark flecks that make three dotted lines which appear to merge towards the tail. Mehrtens, 1987, suggested that females are brown ventrally, whilst males are yellow. It has also been suggested that females have lighter bands and markings on the body. This is not an effective way of judging the sex of H. gigas, as coloring will differ slightly between all individuals. Hatchling and juvenile animals are much darker in coloration and do not have the typical dark eyes of the adults. They more resemble a garter or water snake than their mature counterparts. In captivity hypomelanstic animals have been produced. These animals vary in coloration, from some having only slightly lighter colored saddles, all the way to those that are almost patternless.
, Bolivia
, Paraguay
and northern Argentina
. There may also be populations living in Colombia
and French Guiana
.
produces a secretion with high proteolytic activity. Besides the ability of this large and powerful snake to inflict mechanical trauma, there have been numerous cases of local envenomation and perhaps hypersensitivity, most of which have gone unreported. Prolonged chewing bites may result in painful (sometimes extensive and persistent) swelling, as well as bruising. Nevertheless, the species is regularly kept as a pet, becoming increasingly popular in recent years.
Manning et al. (1999) described a case in which an 18-year-old male pet store employee was bitten on the wrist by a specimen that hung on for 1.5 minutes. There was some mild swelling as a result, but after nine hours the victim claims to have experienced three bouts of muscle paralysis, during which he fell and was unable to move or speak. However, a medical examination did not produce any unusual results. It's possible the symptoms described were the result of anxiety.
Venomous snake
"Poisonous snake" redirects here. For true poisonous snakes, see Rhabdophis.Venomous snakes are snakes which have venom glands and specialized teeth for the injection of venom...
colubrid
Colubrid
A colubrid is a member of the snake family Colubridae. This broad classification of snakes includes about two-thirds of all snake species on earth. The earliest species of the snake family date back to the Oligocene epoch. With 304 genera and 1,938 species, Colubridae is the largest snake family...
species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
found in South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
. It is alternatively known as the false water cobra and Brazilian Smooth Snake. No subspecies are currently recognized.
Common names
Hydrodynastes gigas is commonly referred to as the false water cobra, false cobra, South American water cobra, and Brazilian smooth snake. It is often referred to within the reptile hobby more simply as either a "falsy" or "falsie" or a "FWC", which is an abbreviation of the common name false water cobra. In South America it is sometimes referred to as "Boipevassu".Description
Hydrodynastes gigas is a large colubrid that may exceed 300 cm (9 to 10 ft) in total length when adult. However most H. gigas reach approximately 2 m (6 to 7 ft) in length. H. gigas is of medium body, and is therefore neither particularly heavy nor slender bodied. It is however one of the heaviest colubrid species when full adult size is attained. The common name false water cobra is an allusion to its ability to flatten its neck, similar to a cobraCobra
Cobra is a venomous snake belonging to the family Elapidae. However, not all snakes commonly referred to as cobras are of the same genus, or even of the same family. The name is short for cobra capo or capa Snake, which is Portuguese for "snake with hood", or "hood-snake"...
as a defensive reaction to make it look larger and more intimidating. However, unlike the true cobra the false water cobra stays in a horizontal position when it hoods, rather than standing in a vertical position. H. gigas also can flatten not only its neck but also lower down the body, which is not possible for a true cobra.
Additionally, the pattern and coloration of Hydrodynastes superficially resemble those of true water cobras (Boulengerina
Boulengerina
Boulengerina is a genus of elapid snakes known commonly as water cobras, so named because of their semi-aquatic nature. The genus has two recognized species, which are found in central and southern Africa...
).
The false water cobra has large eyes with circular pupils allowing good daytime vision. The tongue is black, and of the typical snake fashion.
The background colour of a mature specimen is an olive green or brown, with dark spots and bands covering much of its body. The background coloring and banding generally becomes darker towards the end tail of H. gigas. This colouring gives the false water cobra effective camouflage in its natural rainforest environment. The ventral scales
Ventral scales
In snakes, the ventral scales are the enlarged and transversely elongated scales that extend down the underside of the body from the neck to the anal scale. When counting them, the first is the anteriormost ventral scale that contacts the paraventral row of dorsal scales on either side...
are yellow or brown, spotted with dark flecks that make three dotted lines which appear to merge towards the tail. Mehrtens, 1987, suggested that females are brown ventrally, whilst males are yellow. It has also been suggested that females have lighter bands and markings on the body. This is not an effective way of judging the sex of H. gigas, as coloring will differ slightly between all individuals. Hatchling and juvenile animals are much darker in coloration and do not have the typical dark eyes of the adults. They more resemble a garter or water snake than their mature counterparts. In captivity hypomelanstic animals have been produced. These animals vary in coloration, from some having only slightly lighter colored saddles, all the way to those that are almost patternless.
Geographical range
Throughout South America notably BrazilBrazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
, Paraguay
Paraguay
Paraguay , officially the Republic of Paraguay , is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Paraguay lies on both banks of the Paraguay River, which runs through the center of the...
and northern Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
. There may also be populations living in Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
and French Guiana
French Guiana
French Guiana is an overseas region of France, consisting of a single overseas department located on the northern Atlantic coast of South America. It has borders with two nations, Brazil to the east and south, and Suriname to the west...
.
Habitat
H. gigas generally lives in wet, humid and marsh land areas. Typically within the tropical rainforests that are common within its range. However, the false water cobra has also been observed in dryer areas, although this is not its preferred habitat. The preference of wet land as a habitat for H. gigas contributes to its common name of false water cobra.Behavior
H. gigas is primarily a diurnal species. It is also a very active and inquistive snake, which will spend much of the day climbing, burrowing and even swimming. The temperament of FWCs can vary massively between specimens, some are very docile and reluctant to bite, whilst others are very defensive and even aggressive or intimidating. Captive bred specimens can become quite tame and trusting and many exhibit a high level of intelligence.Feeding
In the wild, H. gigas is primarily a fish and amphibian feeder but will take small mammals, birds and even other reptiles. In captivity most are rodent feeders and can quite easily be introduced to other types of food as well.Venom
The posterior maxillary teeth of H. gigas are enlarged and the Duvernoy's glandDuvernoy's gland
The Duvernoy's gland is a gland found in some groups of colubrid snakes. It is distinguished from the venom gland and is not found in viperid or elapid snakes...
produces a secretion with high proteolytic activity. Besides the ability of this large and powerful snake to inflict mechanical trauma, there have been numerous cases of local envenomation and perhaps hypersensitivity, most of which have gone unreported. Prolonged chewing bites may result in painful (sometimes extensive and persistent) swelling, as well as bruising. Nevertheless, the species is regularly kept as a pet, becoming increasingly popular in recent years.
Manning et al. (1999) described a case in which an 18-year-old male pet store employee was bitten on the wrist by a specimen that hung on for 1.5 minutes. There was some mild swelling as a result, but after nine hours the victim claims to have experienced three bouts of muscle paralysis, during which he fell and was unable to move or speak. However, a medical examination did not produce any unusual results. It's possible the symptoms described were the result of anxiety.