Nothing Larger than an Anaconda

Written by TJ Larsen

November 19, 1998

Throughout the ages, human beings have been known to fear what they know little about. Snakes have been incorrectly considered slimy and generally feared because of their mysteriousness for years. Anacondas are the largest and one of the most feared snakes on the planet.  Most of the fear has been a result of mythology and South American lore.  A seventeenth century Jesuit priest, Padre Gumilia, documented that in the llanos of Venezuela anacondas invisibly spray poisonous vapors from their mouths as well as hypnotize their victims. A former curator of reptiles at the New York Zoological Society, Dr. James A. Oliver, referenced a Brazilian news paper that published a claim in 1948 that a 156-foot-long anaconda devoured several army soldiers and knocked over entire buildings.  Many unconfirmed anecdotes about anacondas’ history have made them famous for their size. “The llaneros firmly believe that an anaconda can bite a bull on the nose, knot itself around a tree and stretch to the thinness of a twig until the bull gives up, whereupon the snake squeezes the exhausted bull the death” (Kemper 4).  The fact is that their biology has been almost completely unknown unlike other leg-less reptiles of prey.  There has been minimal observation of anacondas in captivity and no research in the wild until 1992.

John Thorbjarnarson is a herpetologist who was researching crocodiles in Venezuela when he first started turning his attention to anacondas.  He consulted with the Venezuelan Wildlife Department (Profauna) after hearing rumors that anacondas could be found all over the low llanos of central Venezuela.  Before long, Thorbjarnarson began the first study of anacondas in their natural habitat with the Wildlife Conservation Society. His team got right to work on a ranch called El Cedral.  The area floods from May to September and dries up with only a few pools of water and muddy streams by November.  “Comprising over 130,000 acres, ten Manhattan Islands could fit within the boundaries of El Cedral ranch” (Thorbjarnarson 2).  They had their work cut out for them with all that land and no previous knowledge of how anacondas behave in their habitat.  Other local wildlife presented more of a threat to the research than the snakes themselves. Anacondas live in the same pools as piranhas, electric eels, and freshwater stingrays.  While walking through waist-deep water, one has to shuffle his or her feet to prevent contact with a stingray’s poison-tipped tail. Handling the anacondas takes a bit of courage and determination, but for Thorbjarnarson’s crew, it was finding them that proved to be the hardest part.

During the dry-season on El Cedral, the anacondas are easier to locate.  Their olive-yellow skin is glossy with black markings.  Their heads, stripped red, are small in comparison with their massive bodies.  “A 500-pound female anaconda holds the record for the world’s heaviest snake” (Watson 1).  Recognizing their extruding nostrils or the long lump in the mud and vegetation started out as the most effective method of catching the water snake.  This particular species of anaconda (Eunectes murinus) can also be found in the Amazon and the Orinoco river basins.  A second and smaller species (Eunectes notaeus) reside around the rivers of Argentina, Paraguay, and southern Brazil.  Despite what legends say, human beings are not one the anaconda’s preferred meals.  They eat animals as small as frogs and turtles along with larger prey like white-tailed deer.  Two Venezuelan students on Thorbjarnarson’s research team, Jesus Rivas and Maria Munoz have mastered the art of studying anacondas in the wild. They have learned first hand that it easy to prevent getting eaten by the snakes even if they get a bite of you.  Snakes’ teeth are retractable and pushing into the anaconda’s mouth loosens the grip and allows you to escape.  This is useful information, but more importantly, the only time an anaconda would ever become aggressive is if it is handled around the neck.

For over five years, Rivas and Munoz have successfully caught and studied over 450 anacondas while the water levels were low.  Once caught, a sock is taped around the snake’s head in order to blind and calm it down.  Then “the anacondas are marked by clipping a combination of their scales near the base of the tail, and also by noting the unique pattern of light and dark scales on the tail’s undersurface, which acts like a snake ‘fingerprint’; no two are alike” (Thorbjarnarson 4).  The tagged anacondas are always released back into their habitat.  Throughout the first year of research, Rivas and Munoz discovered and tracked their movement and behavior patterns by following anacondas implanted with transmitters. After that, the anacondas could be monitored when the season changed and El Cedral flooded.  Over all, the reproduction process is the most mysterious part of the anaconda.  For two to four weeks, up to a dozen males will coil around one larger female in what has been titled a “breeding ball” in the mud.  DNA tests on the offspring and the potential fathers will determine if only one or all of the surrounding males impregnates the female.  The anaconda does not lay eggs like most snakes, but she does lie in the sun to warm up to seventy embryos.  She also starves herself until she gives birth, so that an aggressive hunt will to hurt the unborn snakes.

Old tales about evil serpents and giant water snakes will always be told, but now the true nature of anacondas is developing as the research continues.  Our fear and superstition have given anacondas more of a reason to fear us.  Ranchers in Venezuela say that if you do not kill an anaconda on sight a curse will be put on you.  Skin trading is illegal and does not seem to threaten the population because for the most part anacondas disgust or frighten people away.  The knowledge that we have been lacking is part of the reason so many people fear the anaconda.  John Thorbjarnarson commented that “in the early part of this century, Theodore Roosevelt offered a sizable reward for anyone who could produce a live snake over thirty feet long, a reward that to this day has gone uncollected” (2).  The longest anaconda caught by his researchers was seventeen feet.  While the studies advance, maybe anacondas will earn more respect for being the world’s largest snake, instead of being feared for it.

Works Cited

Kemper, Steve and Gary Braasch. “If It Moves, Grab It, But Try Not To Get The End

That Bites.” Smithsonian Vol. 27. Issue 6. Sept. 1996: 1-7. (3-11-98)

Watson, Traci. “Snake! In Search Of The Wild Anaconda.” US News & World Report

Vol. 122. Issue 15. 21 April 1997: 1-2. (3-11-98)

Thorbjarnarson, John. “Trailing The Mythical Anaconda.” Americas Vol. 47. Issue 4.

Jul/Aug 1995: 1-6. (3-11-98)