Quite poisonous, I probably got closer than I should have. The beauty of this snake doesn't come out fully in photographs, but this was the best I could do. Found on a night hike in DVFC/DVCA. Despite this species being supposedly rare it was the pit viper I most often encountered. Colours range from green to a yellowish white. However despite any colour differences the inter-scalar spaces are black and the the tip of the tail is a light red. The red tail has been implicated in caudal luring. A behaviour in which neonates worm their tails thereby luring small animals within striking distance. The eyes although white in juveniles becomes bronze in adulthood. This is one of the largest pit vipers with sizes approaching 1.5M and so it should be treated with caution, both because it has an increased strike distance and it can deliver more venom via 1 inch fangs. Pit vipers or Crotalinae, get their name by the recessed infrared radiation (heat) sensing organs (loreal pits) located between the eyes and the nostrils. Such organs provide reliable information for a strike, so that deviation from a target is no more than 5 degrees. Direction and distance are determined by the difference in time required for radiation to hit the first and second loreal pits. Vipers are ambush predators. They don't actively hunt but instead use their heat sensing abilities to their greatest advantage. The snake's diet consists mostly of small mammals, amphibians and reptiles. They slither along trees, plants and the ground following heat trails and chemosensory information gleaned from flickering tongues. Their forked tongue conveys scent molecules to a sensory organ on the roof of the mouth. The distance between the two forks allows for a chemical gradient to form which the snake can follow. Once they have found an ideal spot wherein they are comfortable, relatively protected and immediately adjacent to an animal trail, they sit and wait. Animals like humans use trails through the forest. This is especially true in the dense rainforests of the tropics where trails enable an animal to save a considerable amount of time. The danger however is that in constantly retracing its route, the animal puts itself in danger by any predator that also uses that trail. And since like us, an animal stumbling across a trail will generally follow the path of least resistance, then trails are more busy than one would assume. Though some pit vipers are diurnally active, most avoid the high daytime temperatures by confining their activity to the night. Once prey has been located, the snake judges the distance and then strikes. Vipers can strike from up to half their body length away and can do so in less than a second. The hollow fangs which are stored against the roof of the mouth hinge downwards, bite and inject venom. Pit vipers are unique in that they have a specialized muscle, the muscularis pterigoidius glandulae located between the venom gland and the ectopterygoid. Compression of the muscle results in evacuation of venom from the gland. The toxicity of the venom varies between species and is usually related to size, with larger snakes delivering larger payloads. Pit vipers inject a mixture of cytotoxic and hemolytic enzymes which function as toxins within the body of the prey. The cytotoxic component is responsible for killing and breaking down the cells localized to the injection site by necrosis or apotosis while the hemotoxin destroys red blood cells, and affects the cardiovascular system by decreasing blood flow, and lowering blood pressure, and disrupts clotting by affecting clotting factors. Furthermore, the injected enzymes help to break down the bodily tissues aiding in digestion. Typically the venom doesn't kill the prey instantly, but over the course of hours due to shock to the system. Meanwhile the snake follows the heat trail left behind the prey that is slowly becoming weak and disoriented. The snake will minimize any danger by waiting until the prey is dead before consuming it. After feeding it may retreat to a den or area of safety while it is digesting its prey. A snake may survive weeks between feedings due to its slow metabolism.

Found during a night hike in mixed dipterocarp rainforest of ginseng camp at Maliau basin. Despite this species being supposedly rare it was the pit viper I most often encountered. Colours range from green to a yellowish white. However despite any colour differences the inter-scalar spaces are black and the the tip of the tail is a light red. The red tail has been implicated in caudal luring. A behaviour in which neonates worm their tails thereby luring small animals within striking distance. The eyes although white in juveniles becomes bronze in adulthood. This is one of the largest pit vipers with sizes approaching 1.5M and so it should be treated with caution, both because it has an increased strike distance and it can deliver more venom via 1 inch fangs. Pit vipers or Crotalinae, get their name by the recessed infrared radiation (heat) sensing organs (loreal pits) located between the eyes and the nostrils. Such organs provide reliable information for a strike, so that deviation from a target is no more than 5 degrees. Direction and distance are determined by the difference in time required for radiation to hit the first and second loreal pits. Vipers are ambush predators. They don't actively hunt but instead use their heat sensing abilities to their greatest advantage. The snake's diet consists mostly of small mammals, amphibians and reptiles. They slither along trees, plants and the ground following heat trails and chemosensory information gleaned from flickering tongues. Their forked tongue conveys scent molecules to a sensory organ on the roof of the mouth. The distance between the two forks allows for a chemical gradient to form which the snake can follow. Once they have found an ideal spot wherein they are comfortable, relatively protected and immediately adjacent to an animal trail, they sit and wait. Animals like humans use trails through the forest. This is especially true in the dense rainforests of the tropics where trails enable an animal to save a considerable amount of time. The danger however is that in constantly retracing its route, the animal puts itself in danger by any predator that also uses that trail. And since like us, an animal stumbling across a trail will generally follow the path of least resistance, then trails are more busy than one would assume. Though some pit vipers are diurnally active, most avoid the high daytime temperatures by confining their activity to the night. Once prey has been located, the snake judges the distance and then strikes. Vipers can strike from up to half their body length away and can do so in less than a second. The hollow fangs which are stored against the roof of the mouth hinge downwards, bite and inject venom. Pit vipers are unique in that they have a specialized muscle, the muscularis pterigoidius glandulae located between the venom gland and the ectopterygoid. Compression of the muscle results in evacuation of venom from the gland. The toxicity of the venom varies between species and is usually related to size, with larger snakes delivering larger payloads. Pit vipers inject a mixture of cytotoxic and hemolytic enzymes which function as toxins within the body of the prey. The cytotoxic component is responsible for killing and breaking down the cells localized to the injection site by necrosis or apotosis while the hemotoxin destroys red blood cells, and affects the cardiovascular system by decreasing blood flow, and lowering blood pressure, and disrupts clotting by affecting clotting factors. Furthermore, the injected enzymes help to break down the bodily tissues aiding in digestion. Typically the venom doesn't kill the prey instantly, but over the course of hours due to shock to the system. Meanwhile the snake follows the heat trail left behind the prey that is slowly becoming weak and disoriented. The snake will minimize any danger by waiting until the prey is dead before consuming it. After feeding it may retreat to a den or area of safety while it is digesting its prey. A snake may survive weeks between feedings due to its slow metabolism.