|Mangrove Pit Viper|
Pit vipers (members of the subfamily Crotalidae), although often known for their venom, are fascinating reptiles. These snakes all come from different habits like deserts, jungles, and Asian countries. However, they all are excellent predators. They have heat-sensing organs called pits on the sides of their head which allow them to detect the location of animals or objects that are nearby with incredible accuracy despite the fact that they have very poor eyesight. The crotalines, as they're also called, also have a venomous bite that can be fatal and permanently disfiguring.
The pit viper, a member of the order of Squamata, is a snake with a long, muscular body and a triangular head.  These snakes range in size from small ones that grow to 20 inches to large ones like the Bushmaster which can reach up to three meters long.. They are scaly animals that are also ectotherms, animals that regulate body temperature using external sources. Their colors are also diverse with coloring such as solid yellows, bright greens, and patterned browns. Because it's a true viper, it has a pair of long, poisonous fangs that are folded inside its palate.These snakes also have forked tongues which they use to detect scents.
The one identifying characteristic for all pit vipers are the deep pits located on either side of the head.  Located between the ears and the nostrils, these deep pits are organs that help the animal catch prey. These organs are very sensitive thermoreceptors (sensory nerve endings that respond to changes in temperature) that respond to a wide variety of radiation including ultraviolet radiation. They are comprised of two chambers, an outer chamber and an inner chamber. The snake uses its highly-developed brain to determine the location of any animal that has a different temperature than the rest of the surrounding area. It locates its prey by comparing the input from the right and left pit organs and using that information in relation to its own position. Using these specialized pit organs, the snake is able to capture and attack prey extremely accurately.
Pit vipers reproduce by internal fertilization. The male has a penis-like organ called the hemipenes stored in the tail. The male will deposit the sperm inside the female's cloaca.  Inside the female, the embryos will be covered with membranes and a leathery shell in an amniotic egg (Adam/Levine, 797-805). Most pit vipers are ovoviviparous, meaning the embryos develop within eggs inside the mother but are born alive. The amount of children that a pit viper has varies between species. The children are well-developed when born and can deliver a poisonous bite. They generally remain with the mother for the first two weeks after birth or until their first molt. Certain species of pit vipers are oviparous and lay eggs such as some of the snakes belonging to the genus Trimeresurus.
Ecology Most species of pit vipers live in the Western hemisphere such as the rattlesnakes, but some species live in parts of Asia.Now due to pollution, depleting rainforests, and hunting many populations of vipers have seen a decline in size. Some people in Asia hunt certain pit vipers for their rumored medicinal properties. There is even a liquor called habu sake that is made out of a pit viper.
Crotalines are ambush predators that are generally active during the night. They eat small animals like mice. During the winter, some species such as the rattlesnakes will come together in a den to provide heat for each other.
Unless provoked or threatened, a pit viper is generally not dangerous to humans. However, because of growing human populations and deteriorating habitats, snakes and humans have been meeting more. When provoked, snakes use their elongated fangs to inject venom into the threat. When dealing with humans, it's likely that the bite will have no venom due to a change in timing and size of prey. The toxicity of a pit viper's venom varies between species. Many venoms can be lethal while others are just irritants. The venom is a mixture of enzymes designed to help the snake kill and digest its prey. It destroys tissue, often disfiguring the infected area. Some venom poisons the blood by destroying the red blood cells and thus ruining the oxygen flow to the entire body. People rarely die from the venom of these snakes, but children and the elderly are especially at risk for death. If bitten by a pit viper, one should treat the situation as an emergency and get professional treatment. 
Black-speckled palm viper
Malayan pit viper
(L. muta muta)
(S. catetanus tergeminus)
White-lipped tree viper
Japanese Pit Viper
McGregor's Pit Viper
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