Bothrops atroxBarba Amarilla, Fer-de-Lance, common lancehead

Geographic Range

The common lancehead (also called "fer de lance") is found in the tropical regions throughout Central and South America. There it is quite common in both wooded and open areas (Mattison, 1986).

Biogeographic Regionsnearctic  native 

Habitat

The common lancehead is found throughout the forests of Central and South America. However, it has also been known to invade plantations in search of rodent prey (Phelps, 1981).

Physical Description

The common lancehead has many distinct features of the Viperidae family. The color of this snake can take on many shades for camouflage. It can be gray, brown, olive, or green. This snake also has large, dark, pale, margined triangles with points that meet on the dorsal line. The head is triangular (lance-shaped) and pointed. The common lancehead can grow up to 6.5 feet in length (Phelp, 1981).

Reproduction

The lancehead gives birth to live young. The litters can contain up to 80 babies that are about one foot long. They are born with venom glands and are still dangerous (Carnley, 1996).

Lifespan/Longevity

Average lifespan
Status: captivity8.5 yearsAnAge

Behavior

The lancehead is a hunter that relies on its camouflage to attack prey. The skin color blends in perfectly with the surroundings. Using the pit organs, it can deduce the position of its prey. This snake has also been known to be very aggressive. Conflicts with people have occurred due to its habit of lying in walking trails in wait of prey as well as invading plantations in search of rodent prey (Mattison, 1986).

Food Habits

When young, these snakes feed on lizards and arthropods. The food habits of the adult snake consist of mainly small mammals, which include opossums, birds, lizards, and smaller snakes (Carnley, 1996) To detect their warm blooded prey, these snakes rely on their pit organ located between the eye and nostril. This organ relays thermal information to the snake about the position of their prey (Encarta, 1999).

Economic Importance for Humans: Positive

Common lanceheads have economic importance in the production of anti-venom to treat bites. They also control populations of rodents, which are important crop pests. (Phelps, 1981)

Positive Impactssource of medicine or drug research and education controls pest population

Economic Importance for Humans: Negative

Locals fear Bothrop atrox because of its aggressive reputation and venomous bite. Overall, it is responsible for the majority of venomous snakebites within its forest range. The problem lies in the tendencies of the snake's prey to exploit agricultural land. The common lancehead is a primary concern for plantation and agricultural workers.(Mattison, 1986).

Conservation Status

Bothrops atrox is a quite common snake throughout forested and agricultural land (Phelps, 1981).

Rattlesnake

The only snake from the Americas on the list, the Rattlesnake is easily identifiable by the tell tale rattle on the end of its tail. They are actually a part of the Pit Viper family, and are capable of striking at up to 2/3rd their body length. The Eastern Diamondback in considered the most venomous species in North America. Surprisingly, juveniles are considered more dangerous than adults, due to their inability to control the amount of venom injected. Most species of rattlesnakes have hemotoxic venom, destroying tissue, degenerating organs and causing coagulopathy (disrupted blood clotting). Some degree of permanent scarring is very likely in the event of a venomous bite, even with prompt, effective treatment, and can lead to the loss of a limb or death. Difficulty breathing, paralysis, drooling and massive hemorrhaging are also common symptoms. Thus, a rattlesnake bite is always a potentially fatal injury. Untreated rattlesnake bites, especially from larger species, are very often fatal. However, antivenin, when applied in time, reduces the death rate to less than 4%

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REPTILES - RED BELLIED BLACK SNAKE

The venomous Red-Bellied Black Snake grows to lengths of up to two metres long, and has striking colouration. With stunning red edges to its belly scales and a shiny black back, this snake surely ranks amongst Australia's most stunning venomous snakes. The Red-Bellied Black snake is most active during the day, although they may also be seen on hotter evenings.

Habitat

The Red-Bellied Black Snake can be found inhabiting most forest types near permanent watercourses or swamps in eastern and south-east Australia.

Diet

The Red-Bellied Black Snake's diet consists of frogs, other reptiles and mammals. Usually seen around cool, wet areas the Red-Bellied Black Snake is particularly fond of frogs, making the Cane Toad a big problem. If they even bite a Cane Toad its all over. It's hard to believe that this beautiful snake could suffer so badly as the result of the introduction of one alien species.

Breeding

Mating occurs in spring with combat between rival males occurring in this period. During combat, the snakes bodies are intertwined with their heads raised. They do this in attempt to place their head higher than that of their opponent. When pregnant, female Red-Bellied Black snakes are known to aggregate and bask in the sun together. January to March is when between five and forty young are born in membranous sacs from which they emerge from shortly after birth.

Status

Local populations were almost driven to extinction by the introduction of the Cane Toad. If a snake tries to consume a toad, they will fall victim to the toad’s poisonous gland secretions. It does however appear now that some of these snakes are finally learning to avoid the Cane Toad and their numbers are beginning to recover.

Golden lancehead

The Golden lancehead (Bothrops insularis) is a highly venomous pit viper species endemic to the Queimada Grande island or as it's known in colloquial English "Snake Island". ​

The island is located about 40 miles off the coast of Sao Paulo state, in Brazil and it's size is roughly around 110 acres. ​

 also uninhabited and travel to the island is forbidden by the Brazilian navy, and there is a good reason, it is home to hundreds of thousands of venomous golden lancehead snakes.

The island is a subtropical or tropical moist forest containing several different types of habitats including forest, clearings, and shrubs. The climate is very mild, and the temperatures never fall below 64ºF (18ºC), or over 72ºF (22ºC). 

They can usually be found seeking shelter among leaf litter or in rock crevices, especially during unfavorable weather or after having just ingested a prey. But are also found in the trees hunting for prey. The golden lancehead grows to an average length of 28 inches (70 cm) but it's known to reach 46 inches (118 cm) in maximum length.

The snake's color pattern consists of a series of triangular or quadrangular blotches, that may be broader or narrow, and alternating or opposite along the back overlaid in a pale yellowish brown ground color. The belly is a uniform pale cream or yellow, and they lack a well-defined post-orbital stripe. When in captivity, their yellowish color often becomes darker

Their common name "lancehead" refers to the distinctive head shape of all Bothrops genus snakes, which is elongated and comes to a point at the nose.

The golden lancehead has a longer tail than the Jararaca, its closest relative, which probably an adaptation to help them maneuver through the trees found in the island.

Venom / Bite

Since the golden lancehead only inhabits an area uninhabited by humans, there has never been a recorded bite by one, but other lancehead species are responsible for more human deaths than any other snakes in both North and South America.

The chemical analysis of their venom suggests that it's 5 times more potent than that of their cousin the jararaca, and is also the fastest acting venom in their genus. The mortality rate for other lancehead species envenomations is around 7%, if the victim doesn't receive medical treatment, but even if the patient receives treatment the bite is fatal on 3% of the cases. 

The effects of lancehead venom include local pain and swelling, nausea and vomiting, blood blisters, bruising, blood in the vomit and urine, intestinal bleeding, kidney failure, brain hemorrhage and severe necrosis of muscular tissue.

Lancehead snakes have an hemotoxic venom that eats away at flesh and tissue to help digest the prey before they swallow it, but the golden lancehead also has some neurotoxic components in their venom to help killing the prey.

Diet / Feeding

Their diet consists mostly of perching birds, but they have been reported to eat lizards or even resort to cannibalism. The newborn and juvenile snakes prey mainly upon invertebrates. Because there are no mammals native to the island Queimada Grande, this has undoubtedly had a profound impact on their evolution.

Reproduction

The golden lancehead mating season occurs during August and September, and these vipers are known to mate using both the ground or trees. Like most other viper species, the golden lancehead gives birth to live young.

The average litter size around 7 newborns, and there is no recorded data about their size at birth, but one would expect it be similar to that of the Jararaca (about 10 inches).

Conservation / Threats

In the IUCN Red List the golden lance head is classified as critically endangered, this is due to several factors, but the main threat to the species is the habitat destruction. In the past, fires were deliberately started on the island in an attempt to eradicate the snakes so it could be used for agriculture.

To maintain the lighthouse on the island, the Brazilian Navy has also contributed to habitat destruction by the removal of vegetation. The species was also plagued by over harvesting from scientists.

The island of Queimada Grande is the only place in which these snakes are found in the wild, but it can only support a limited snake population due to its small size of only 43 hectares.

This also leads to a large amount of inbreeding within the population and the occurrence of "intersexes" (specimens born with both male and female reproductive parts) this is harmful because most of the intersexes are born sterile

Did You Know?

The australian inland taipan  bite contains venom enough to kill up to 100 full grown men. 

Scientific classification

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Viperidae
Subfamily: Crotalinae
Genus: Bothrops
Species: B. insularis

Eastern Brown Snake

Don’t let the innocuous name of this snake fool you, 1/14,000 of an ounce of its venom is enough to kill an adult human. Coming in a variety of species, the Eastern Brown snake is the most venomous. Unfortunately, its preferred habitat is also along the major population centers of Australia. The Brown snake is fast moving, can be aggressive under certain circumstances and has been known to chase aggressors and repeatedly strike at them. Even juveniles can kill a human. The venom contains both neurotoxins and blood coagulants. Fortunately for humans, less than half of bites contain venom and they prefer not to bite if at all possible. They react only to movement, so stand very still if you ever encounter one in the wild. [Image Source]

RHABDOPHIS TIGRINUS FORMOSANUS Asian Tiger Snake

FamilyColubridae, subfamily Natricinae

 

Max. length100 cm

 

Occurrence in Taiwan

Throughout Taiwan, at altitudes above 1500 m.Rare. (Distribution map)

 

Global Distribution

This subspecies is endemic to Taiwan.

 

Description

 

Small to medium-sized snake; total length up to 100 cm. There are 15-19 (17-19 at mid-body) rows of scales, all are strongly keeled. Head is oval and distinct from neck; body is moderately stout; tail is moderately long. Eye is medium to large; iris is dark brown and pupil is round, jet black, surrounded by ring of gray. Tongue is maroonish. The snake has a pair of nuchal glands and enlarged rear fangs (not directly connecting to venom glands). Upper head is olive at least anteriorly; there is a thick, curved cross band of yellow on the nape, to which a black cross band adjoins in the front and rear. The supralabials are yellow with black sutures, the black areas along the sutures below eye are broad. Upper body and tail bear green/yellow/orange and black spots arranged in alternating rows (totally 5 rows), creating a checkered appearance. Ventral head is whitish. Ventral scales on body and tail are blackish with (irregular) posterior margins of light green/yellow. Anal scale is divided and subcaudals are paired.

 

Biology & Ecology

This diurnal opistoglyphous (= rear-fanged, see footnote(1)) snake inhabits humid environments, including mountain rivers, creeks, and forest floors. It preys on frogs and toads, and occasionally on fish or snakes. Females produce 8-47 eggs per clutch in summer; hatchlings measure about 16 cm in total length. When threatened, the snake may rear its head and neck, and expand its neck transversely like a cobra.

This species is also the only known snake that is venomous and poisonous at the same time. (For the difference between the terms 'venomous' and 'poisonous' see footnote (2)).

Here's how:

POISON:

The defensive behavior of this snake is very unusual.When threatened by a predator, the snake arches its neck toward the attacker and releases the contents of paired nuchal glands that lie in the dorsal skin. The product of those glands is distasteful and irritating to the eyes and contains compounds similar to those found in the skin glands of toads. (Source)          

The origin of the poison in these glands is a highly interesting aspect of this species, and was explained for the first time in a 2007 study by Hutchinson et al.The study shows that Rhabdophis tigrinus becomes poisonous by sequestering toxins from its prey, which consists of venomous toads. The process allows the snakes to store in their neck glands some of the toxins from the toads they have eaten:

Analyzing differences between snakes living on toad-rich and toad-deficient islands in Japan, researchers led by Deborah A. Hutchinson of Old Dominion University in Norfold, Virginia, found that the Japanese grass snake or Yamakagashi, as the snake is known locally, did not manufacture its own venom, but instead relied on that found in toxic toads: the researchers found that snakes living on Japan’s toad-free island of Kinkazan lacked the toad’s toxic bufadienolide compounds completely. Snakes from Ishima, where toads are plentiful, had high levels of bufadienolides. R. tigrinus from Honshu, where toad numbers vary, displayed a wide range of bufadienolide concentrations. Feeding R. tigrinus hatchlings toad-rich and toad-free diets confirmed these results.

The study also found that snake mothers with high concentrations of the toxin are able to pass bufadienolide toxin on their offspring, helping protect them from predators. The Yamakagashi stores the sequestered toxins in 'a series of paired structures known as nuchal glands in the dorsal skin of the neck,' according to the researchers. When threatened, the snake takes a defensive position that exposes the toxin-containing nuchal glands to predators.

While sequestering defensive toxins from prey is unusual among terrestrial vertebrates, it is not unknown. Research published last year by Valerie C. Clark of Cornell University showed that poison dart frogs (Dendrobates species) and their Madagascar counterparts, the Mantella frogs, sequester toxic skin chemicals, called alkaloids, from the ants they eat. These alkaloids protect the frogs from predation. Similarly, some garter snakes are known to store tetrodotoxin from ingested newts while birds in New Guinea appear to sequester poisons from insects. (Source) 

The NewScientist notes:

What is more, when attacked, snakes on different islands react differently. On Ishima, snakes stand their ground and rely on the toxins in their nuchal glands to repel the predator. On Kinkazan, the snakes flee. 'Snakes on Kinkazan have evolved to use their nuchal glands in defence less often than other populations of snakes, presumably due to their lack of defensive compounds,' says Hutchinson. Moreover, baby snakes benefit too. The team showed that snake mothers with high toxin levels pass on the compounds to their offspring. Snake hatchlings thus also enjoy the toad-derived protection.

More details on this studycan be found here. The study itself, 'Dietary sequestration of defensive steroids in nuchal glands of the Asian snake Rhabdophis tigrinus' by Deborah A. Hutchinson, Akira Mori et al. is available here.

 

VENOM:

Many members of the family Colubridae that are considered venomous are essentially harmless to humans, because they either have small venom glands, relatively weak venom, or an inefficient system for venom delivery. While Rhabdophis tigrinus has small venom glands and delivers its venom inefficiently, saidvenom is certainly not weak.Although this snake is reluctant to bite, even defensively, the bite has been known to cause fatalities in humans. The venom acts very slowly, inhibiting the ability of the blood to clot and causing death by hemorrhage:

"Three cases of serious envenomation by this species are reported (in Japan), all marked by delayed, spontaneous, superficial hemorrhaging and profound impairment of normal blood coagulation. In two cases these phenomena were accompanied by signs of severe internal hemorrhaging and hemolysis. Other symptoms may have resulted from transitory involvement of the central and autonomic nervous systems. Therapeutic measures applied in these cases are described, including the apparently effective use of a systemic antihemorrhagic drug. It is concluded that R. tigrinus is a dangerously venomous snake and potentially lethal to man.(Source)

For this reason, the small colubrid snakes of the genus Rhabdophis have a shady past in the pet trade. Because they resemble certain harmless garter snake-like species, they were imported into the U.S. and U.K. under the wrong names, and ended up causing medically-significant emergencies when they bit their new owners. (Source)

The website www.toxinology.com provides a detailed breakdown of the contents and clinical effects of R. tigrinus' venom.

 

Etymology

Rhabdophis comes from the Greek words rhabdos,meaning "rod" or "wand", and ophis, meaning "snake";

tigrinus is Latin for "tigerlike";

formosanus denotes the distribution of this subspecies, namely the island of Taiwan (formerly Formosa).

The Chinese name 台灣赤煉蛇 means "Taiwan (台灣) Red (赤) Smelted (煉) Snake (蛇)".

 

Footnotes

(1) "Opisthoglyphous snakes are similar to aglyphous (fangless) snakes, but possess weak venom, which is injected by means of a pair of enlarged teeth at the back of the maxillae (upper jaw). These "fangs" typically point backwards rather than straight down, possess a groove which channels venom into the prey, and are located roughly halfway back in the mouth, which has led to the vernacular name of "rear-fanged snakes".(Source)

(2) The distinction between venom and poison

There is a difference between organisms that are venomous and those that are poisonous, two commonly confused terms applied to plant and animal life:

- Venomous...refers to animals that deliver (often, inject) venom into their prey when hunting or as a defense mechanism.

- Poisonous, on the other hand, describes plants or animals that are harmful when consumed or touched. A poison tends to be distributed over a large part of the body of the organism producing it, while venom is typically produced in organs specialized for the purpose(Source)
 

 

FURTHER INFO

Reptile Database

Wikipedia

Discussion of R. tigrinus on Dr. Bryan G. Fry's Venomdoc Forum

Taxonomic Status of the Taiwanese Populations of Rhabdophis tigrinus

Yellow-bellied sea snake (Pelamis platurus)

The Yellow-bellied sea snake has a paddle-shaped tail and distinctive colouring with a dark back contrasting with paler sides and belly in many patterns. Their average total length is around 1 metre.

Their geographic range is wider than that of any other reptile species, except for a few species of sea turtles. It extends from the east coast of Africa, from Djibouti in the north to Cape Town in the south, across the Indian Ocean, the Pacific, south as far as the northern coast of New Zealand, all the way to the western coast of the Americas, where it occurs from northern Peru in the south (including the Galápagos Islands) to the Gulf of California in the north.

This species lives in the surface layers of the open ocean and drifts passively in warm currents. It is quite helpless on land because their compressed shape makes them roll onto their side and sea snakes washed onto beaches during storms seldom manage to return to the sea.

They feed on small fish only, which they make immovable with their venom. The yellow-bellied sea snake is about ten times more venomous than the Egyptian cobra (Naja haje) but it delivers a much smaller quantity of venom per bite. They hunt by cautiously approaching their prey or by waiting motionless at the surface and ambushing fish that come to shelter underneath it. With its mouth open the snake makes a rapid sideways swipe to snare any fish that comes too close.

Unlike most other species of sea snake, the Yellow-bellied Sea Snake does not seem to have many predators. The bright colouration of this species serves as a warning, not only that the snake is highly venomous, but also unpleasant and possibly even toxic to ingest.

They are capable of bursts of speed of up to 1m/sec when diving, fleeing and feeding. When swimming rapidly, they sometime carry their head out of water.

Yellow-bellied Sea Snakes often are found in large numbers in long lines of marine debris. These “slicks” form in calm seas and consist variously of debris, foam and scum. In some areas, such as the Gulf of Panama in the eastern Pacific Ocean, the slicks can be from 1 to 300 m wide and many kilometers long. Several thousand snakes may be associated with a single slick.

Females give birth to 2 to 6 live young with a gestation period of about 6 months. The young (around 250 mm in total length) are born with substantial fat reserves but they will feed on their first day of life.

As Yellow-bellied Sea Snakes live in open waters they have little access to hard objects, such as coral, to rub against when the skin needs to be shed. Instead the snake uses a knotting behavior where it coils and twists upon itself, sometimes for hours on end, to loosen the old skin. The knotting behaviour also helps to remove organisms such as algae and barnacles attached to their skin.

Most sea snakes are able to respire through their skin. This is unusual for reptiles, because their skin is thick and scaly, but Yellow-bellied Sea Snakes can obtain 20% of its oxygen requirements in this manner, which allows for long dives.



Yellow-bellied sea snake
Image © HeterodonPA from Flickr


Yellow-bellied sea snake 
Image from Searunner


Tail of the Yellow-bellied sea snake