constrictors are a snake that squeezes their prey to death for example a python or a anacondaThese are the five constrictor species that grow large enough to actually harm people.  However, even the largest individual specimens of these species would have trouble consuming an adult human.  They are not in any particular order, as it is difficult to determine, factoring in size, temperament, and habitat; which exactly is the most dangerous to people.     

And next, of course, is the legendary Anaconda.  The name "Anaconda," when used in reference to colossal snakes, typically refers to the Green, or Common, Anaconda.  There is a smaller species, called the Yellow Anaconda, which tops out around 12 feet, making it significantly smaller than its famous cousin.  The Green Anaconda is quite possibly the most feared constrictor and one of the most feared snakes in the world.  They are the heaviest (not necessarily the biggest) snakes in the world.  There is much debate on the true maximum size of these snakes.  Many say that the average length is somewhere in the low to mid 30's (feet).  However, there are (un-documented) accounts of specimens reaching up to 40 feet, though these are mostly regarded as exaggeration.  These snakes have the most obvious difference between males in females, being that females are much bigger than males.  The Anaconda is the only Boa on this list, the others being all pythons.  Being Boas, Anacondas bear live young, and do not lay eggs.  Litters are usually 20-40 babies, but can be up to 100.  Female Anacondas will eat babies that do not survive birthing. Anacondas can weigh up to 200 pounds, and are very thick, heavy-bodied snakes.  There are many reports of these reptiles consuming children and pets in South America, but very few are confirmed.  Anacondas are primarily water-bound snakes, and stick to rivers and water banks.  Anaconda tracks are common on Amazonian beaches.

Lastly, there is the Reticulated Python.  This is the longest species of snake in the world.  Adults typically exceed 32 feet in length and can weigh up to 190-200 pounds.  They are very slender for their length and need to be incredibly long to be the same weight as an Anaconda a fraction of one's length.  These snakes are native to Southeastern Asia, through Indonesia, down toward the Indo-Austrailian Archipelago, and through the Philippines.   These snakes are very feared because of their size, but do not usually voluntarily associate with humans.  There are few confirmed instances of these snakes eating people and pets.  Their primary diet consists of apes and monkeys and other small mammals, and as such, these snakes are incredible climbers.  They will throw coils around a tree and constrict their muscles, gaining a good grip.  Once they are firmly gripped to the tree, they will throw another loop of their body upward, and re-tighten their coils.  Despite how awkward this process may sound, they are very adept at performing it.  These snakes are remarkably fast in the trees.  Also, like most pythons, they can employ methods of ambush.  They have beautiful patterning, including yellow striping, which breaks up their outline on the forest floor, camouflaging them perfectly.  Whenever prey strays too close, the snakes can explode from the ground and constrict immediately, trapping whatever has wandered to them.  There are seven documented cases of Reticulated pythons killing humans, dating back to the early 20th century.  Four are confirmed and only two are in the United States.  These pythons are not usually very aggressive, but when denied food or cornered, they can and will fight back to the best of their ability.

    On an even more fascinating note, the largest known snake in the world is a Reticulated python.  For many years, there were accounts of an Asiatic tribe known as the Kubu who were said to worship a 50 foot Reticulated Python, whose name translates roughly to "Fragrant Flowers."  It is said that they revere this snake as their God.  But reports of such monsters rarely go unnoticed.  It wasn't long until scientists from many different countries were interested in finding this colossal snake-god.  One of which was a researcher from the United States.  He contacted the Kubu tribe while they were trading in a local town, and spoke to their leaders.  After three years of negotiations, the Kubu leaders finally agreed to give Fragrant Flowers to the researchers.  However, when the snake was finally given and measured, it was discovered that the monster serpent was only 36 feet long, eight feet short of a world record (also a Reticulated python), and a seeming far cry from the 50 foot God that had been described.  Local villagers believe that while the Kubu tribe was pretending to negotiate for three years, they were actually out hunting for the second-largest Reticulated python they could find, and instead gave this substitute to the researchers.  Either way, the researchers were disappointed and instead left the monstrous serpent to a local zoo, where it soon became the primary attraction.  Now, nearly 10 years later, the snake is much closer to his legend at a whopping 48 feet long.  He wears in at over 900 pounds and eats three dogs (yes, dogs) a week.  This snake-- whether the Kubu God Fragrant Flowers, or not-- is now the largest known snake in the world and bears the title of the largest reptile in captivity.