The Golden lancehead snake, scientifically known as Bothrops insularis
is
one of the most venomous snakes in the world. The snake is endemic to
the Ilha de Queimada Grande Island, popularly known as Snake Island. The island,
situated about 90 miles off the coast of the Brazilian state of Sao
Paulo, covers an area of 110 acres. Snake Island consists of tropical
and subtropical moist forests, shrubs, and open spaces. At first glance,
the island seems like one of those tropical destinations everyone
dreams about. However, the island is home to thousands of venomous
snakes that inhabiting the island, making it one of the most dangerous
places on earth. Golden lancehead snakes present on the island are also
not safe on the island because they face threats from poachers, habitat
degradation, and diseases. In the last 15 years, their population has
declined by nearly 50% by some estimates. The species is currently
listed as critically endangered by the International Union for
Conservation of Nature. If urgent action is not taken, conservationists
are concerned that the species, which is only found on the island, might
be driven to extinction.
Importance Of The Golden Lancehead Snake
People using high-blood pressure medication often take captopril or
its derivatives, a lifesaving drug that is developed from toxins
obtained from the lancehead viper. According to Zoltan Takacs, founder
of the World Toxin Bank,
the use of snake venom in medicine, opened up a new class of medication
known as ACE (angiotensin-converting enzyme) inhibitors, currently used
to treat over 40 million people around the world. The approval of captopril by the FDA in 1981,
helped push the idea that venoms could be used in the creation of
modern medicine. Since then, venom based medicine has flourished. The
boom has also prompted scientists from different parts of the world to
seek out rare and venomous species of snakes in search of more potent
drugs.
Golden Lancehead Snake Bites
Experts believe that a bite from the lancehead snake on a human
carries a 7% chance of death. Even with treatment, humans still face a
3% chance of dying. Venom from the snake is likely to cause brain
hemorrhaging, kidney failure, intestinal bleeding, and necrosis of
muscular tissue. Lancehead viper venom is hemotoxic, which means that it
destroys red blood cells, disrupts blood clotting, causes organ
degeneration, and tissue damage. The venom thus helps digest the prey
before the snake swallows it. The venom is also known to have neurotoxic
properties, meaning that it can cause muscle paralysis, respiratory
difficulty, and death. Chemical analysis of the snake’s venom indicates
that it is five times more potent than that of its mainland cousin,
Bothrops jararaca.
The venom also acts faster than that of its cousins. Despite being one
of the most venomous snakes in the world, there has never been a
recorded snake bite on humans. There are, however,
several legends about fatalities on the island.
One such tale tells of a fisherman who strayed and decided to search
for bananas on the island, his body was discovered days later in his
boat, with snake bite marks on it. From 1909 to the 1920s, there were a
few people who lived on the island to run its lighthouse. According to
other local tales, the islands last lighthouse keeper and his entire
family died after numerous snakes slithered through the windows of his
home and attacked them. Operations at the lighthouse have since been
automated and only require annual maintenance services from the
Brazilian Navy. The island is also currently uninhabited, and adventure
travel to the island is not allowed by the authorities. However, a few
scientists are allowed on the island to study the snakes. The scientists
also occasionally milk golden lancehead snakes for their venom, which
is used in developing medication.
Diet
Golden lancehead snakes feed on perching migratory birds that
stopover at the island and lizards. There are also incidents of
cannibalism among the snakes. Golden lancehead newborns and younger
snakes feed on invertebrates. Scientists believe that
about 11,000 years ago,
a rise in sea levels gradually separated the Ilha da Queimada Grande
Island from mainland Brazil, leading to the isolation of the species.
The snakes, therefore, evolved over thousands of years on a different
path compared to their mainland cousins. A lack of ground predators
meant that they reproduced rapidly. However, the only challenge was that
the island also lacked ground prey. The snakes, therefore, slithered up
the trees to hunt migratory birds. Golden lancehead snakes also evolved
one of the most potent venoms in the world that kill prey almost
instantly.
Poaching And Hunting
Golden lancehead snakes are in very
high demand in the black market.
Wealthy animal collectors from around the world are particularly
interested in the species due to their uniqueness. Overzealous
scientists, eager to make medical breakthroughs, also drive the high
demand on the black market. The island is therefore frequented by
wildlife smugglers keen to cash in on the lethal vipers. Experts
estimate that a single golden lancehead snake can go for between $10,000
and $30,000, which is an attractive sum of money for the poachers.
Research suggests that the
illegal removal of individuals from the island could be a reason behind
the decline of the golden lancehead population. Poaching is
particularly harmful to the species since it targets the largest and
thus the oldest individuals, which are also the most reproductively
mature. Targeting such older snakes means that fewer snakes in the
population reach old age classes leaving higher proportions of younger
snakes.
Studies also reveal that body size is usually positively related to fecundity,
especially in female reptiles. A decline of older and larger
individuals could, therefore, lead to a drop in average population
fecundity, which negatively affects population growth. Similar trends
are observed in the green python (
Morelia viridis) populations
in Oceania. Targeting adult females can, however, be advantageous when
establishing colonies of captive-bred snakes.
Habitat Degradation Through Fires
In the past, fires have been deliberately started on the island in an
attempt to eliminate the golden lancehead snakes so that
acreage on the island can be utilized for plantation agriculture. The
island’s name, Ilha da Queimada Grande, is a Portuguese title that
loosely translates to Slash and Burn Fire or Big Burnt Island. The name
refers to an attempt made by early developers to establish a banana
plantation on the island through the slash and burn method, which is an
environmentally destructive technique. Such activities likely led to the
death of a significant population of snakes on the island. Numerous
snakes on the island have eventually forced the developers to abandon
their plans.
Habitat Destruction On Mainland Brazil
Conservationists are also concerned about
habitat destruction on mainland Brazil.
Although the snake island is miles away, many of the birds that arrive
on the island (a primary source of food for the snakes) originate from
mainland Brazil. The golden lancehead snake preys on two out of 41
migratory birds that seasonally arrive on the island. The
tyrant flycatcher is the
most common prey among adult pitvipers. The bird is found on the coast
of southeastern Brazil towards the end of the wet season (austral
summer). Low numbers of tyrant flycatcher birds making stops on the
island in the corresponding season results in low survival rates of the
snake population due to a scarcity of food. Prey availability also
affects reproduction. Golden lancehead snakes have lower breeding
frequency than the B
. jararaca
species found on the mainland,
which enjoys relatively higher prey availability rates. The observation
indicates that there is a close relationship between prey availability
and population trends. Migratory birds, therefore, help maintain a
delicate balance on the island’s ecosystem. Land clearing and the
destruction of forests on mainland Brazil essentially robs migratory
birds of their natural habitat leading to a decline in the bird
population, which consequently affects the delicate balance on the
island. Such human-made destructions have led to a steep decline in the
number of migratory birds making stopovers on the island, which means
less food for the snakes.
Habitat Destruction Through Vegetation Clearing
The Brazilian Navy has also been accused of
destructive vegetation clearing around the
lighthouse. Such activity negatively affects the habitat on the island,
which consequently affects the snake population. Since the species is
only found on the island, any alteration of its environment can have
potentially devastating effects on the snake population.
Conservation Of The Species
Experts suggest that conservation of the golden lancehead’s habitat
and the eradication of poaching are the most sustainable methods of
saving the species. New innovative ideas are also being developed to
help save the species. Artificial insemination is currently being
researched by
Rogerio Zacariotti,
a conservation biologist, as a means of preserving the species. The
technique has been successfully used to aid in the reproduction of other
endangered species, but it has yet to be perfected in snake
reproduction. The procedure, as done by Zacariotti, involves catching a
live venomous snake, restraining it, and then massaging the sperm toward
the exit where it is collected. The collected specimen is then used for
future implantation.
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