Cryptic killer, Bothrops atrox- common lance head pit viper of the Amazon

The lance head pit viper found in South and Central America claims the most lives each year. Out of all the venomous snakes in the neotropics, this snake is the most common. They can be found from urban sprawl areas to the depths of the rainforest.
The most common places to find them are the edges or ecotones where two habitats or biomes converge. These ecotones can be a sharp difference or a gradual change over space. Diversity and biomass are always more dense in these areas due to the mixing of ambients.
Some examples of ecotones are the shores of lakes, rivers and the edges of forests or clearings.

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Some of these ecotones can be very dynamic in the Amazon River Basin due to the rise and fall of the river that invades lowland forest annually. The snakes will stay right on the edge in hopes of a chance at some passing prey( which also use ecotones for foraging).

The lance heads generally like drier areas and will avoid sitting for long periods in water. They are often found on top of fallen logs where they are coiled basking in the sun or awaiting prey.

All neotropical pit vipers have hemotoxic venom which attacks tissue and blood cells causing them to lyse and burst after the bite. The snakes need a powerful venom to detain their prey quickly as to not need to track it for long distances. The pit vipers will bite, inject and retract . They do not generally hold onto the prey unless it is very small and does not pose much bodily threat to the snake itself. The victim will not make it very far after the bite, the adrenaline rush pumps the venom quickly throughout the body making it a swift demise.

Using their sense of smell (tongue flicking scent particles to the Jacobson’s organ) and their heat seeking capabilities ( loreal pits ), the prey is quickly tracked down and swallowed whole.
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Recent studies about the life cycle of these serpents suggest a variability of venom potency and compounds present in the snake throughout different stages of its life. Younger snakes have a mix of venom that will bring their prey down quicker than adult venom. Adult venom has a different composition that allows the venom injected to digest prey internally quicker. The reasons for this difference have been explained in a variety of ways but the most logical is as follows.

The smaller snake needs to kill quickly so the prey does not go too far. They are small and vulnerable needing nutrition quickly. They generally hunt small frogs and lizards that can quickly gain distance away from the snake. Once the snake has found its prey, it will swallow and digest for several days.

The adults have the advantage of body mass and do not need to worry about missing a meal as much as a juvenile. They generally take prey with a higher body mass so injecting extra digestive enzymes makes it easier for them to metabolize in the long run.

Another difference between adults and juveniles is the sulfur colored tail of newborns and juveniles. The tail is used a lure for small amphibians or reptiles. The young snake sits coiled with its tail in front of its striking range. The tail moves in a way imitating a grub or worm slithering out of the leaf litter. When the prey item goes in to range sometimes even biting the lure, the young snake will strike, securing its next meal.

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Juveniles also use their tail as a warning to potential threats. They will shake their tail on the leaf litter violently enough to make a rattling sound. The sound alerts potential threats to stay away. This feature is the reason why many locals believe the young snake to be a rattle snake. There are no rattlesnakes in lowland Amazon.They refer to the young lance heads as “cascabelle”( Spanish for rattlesnake)

Adults have a warning alarm also. On several occasions, I have witnessed large adults flashing the white of their chin to potential threats. Due to their incredible camouflage, the flashing stands out especially at nighttime. Upon closer inspection, it is clear the presence of the large viper sitting and waiting.

Another very interesting thing about these snakes and mostly all vipers and boas. They are ovoviviparous , this means that they give live birth. Yes, live birth. The eggs are retained inside the snake. The complete development occurs inside the mother and when ready, they are born one by one.

For the most part,the snakes want to be left alone and will try hard to flee in need be. Young snakes instinctively bite at anything not knowing any better. Adult snakes may even strike in an opposite direction if you get too close. They are only warning you. The gravid (fertile with eggs)adult female will try its hardest to avoid a conflict. Their venom and fangs cost them energy and they would not want to waste them on something that is not food.

One day I was exploring an area that was about to be fillied in by floodwater. I followed the edge where the water was encroaching into the forest looking for absolutely anything to eat from fish to jungle rats or even fallen fruits. Movement caught my eye up ahead in the water so I continued up the edge not taking my eye off the area where there was the disturbance. Suddenly I heard a whoosh and out of the corner of my eye, I watched a large adult lance head strike in front of me. The snake was less than 15 inches from my right foot, coiled under a hanging palm frond.

I jumped back as she struck again but ahead of me and not at me. My instincts got the better of me and the 22 inch razor sharp machete in my hand sliced her in two revealing many soft white eggs. I was shocked, surprised utterly speechless not only because I came that close to being bit but because she had every opportunity to bite me but she didn’t. I also felt remorse for chopping her in two because she spared me my life and I did not repay the favor.

I gathered her and brought her back to camp for lunch. After gutting, skinning and seasoning with local veggies, I wrapped it all in leaves and cooked it patarashca style over the fire. It was similar to older free range chicken, kind of stringy but sustenance none the less.

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This example goes to show that the snakes are not out to get you. A bite to a human is a mistake, more often fatal for the snake more so than for the human if he/she can get to anti venom soon. It is recommendable to get your first dose of antivemom within the first four hours of the bite. Recovery from these bites is quite common after receiving the proper antidote.

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The majority of larger villages in Peru have antivenom available not too far away. There is a mini clinic in the village of Oran where the doctors have saved several lives through first response dosage of antivenom. Since the installation of the clinic there have been no fatalities by snakebites in Oran for the past five years.

In the ten years, working and exploring the Amazon,I have never been bitten by a venomous snake, nor have any of my clients. My guests travel with the most experienced jungle guides that have very keen eyes for these creatures. Even with their keen eyes though,it is very possible to overlook an individual, sitting silently waiting.
Otorongo Expeditions

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One Response to Cryptic killer, Bothrops atrox- common lance head pit viper of the Amazon

  1. Mary Beth Clark says:

    Very interesting Anthony! I have always been a big fan of snakes! Did you eat the eggs too?

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