This article is about snakes. For other uses, An anaconda is a large, non-venomous snake found in tropical South America. Although the name actually applies to a group of snakes, it is often used to refer only to one species in particular, the common or green anaconda, Eunectes murinus, which is one of the largest snakes in the world.

Anaconda may refer to: Any member of the genus Eunectes, a group of large, aquatic snakes found in South America. Eunectes murinus, a.k.a. the common anaconda, the largest species, found east of the Andes in Colombia, Venezuela, the Guianas, Ecuador, Peru, Bolivia, Brazil and on the island of Trinidad. Eunectes notaeus, a.k.a. the yellow anaconda, a smaller species found in eastern Bolivia, southern Brazil, Paraguay and northeastern Argentina. Eunectes deschauenseei, a.k.a. the dark-spotted anaconda, a rare species found in northeastern Brazil and coastal French Guiana. The giant anaconda, a mythical snake of enormous proportions found in South America. Any large snake that "crushes" its prey (see Constriction). Applied loosely.

Etymology

The name was first used in the English language in 1768 by R. Edwin in a colorful description of a large snake found in Ceylon (now Sri Lanka), most likely a reticulated python, Pytho reticulatus. The account, which explains how the snake crushes and devours tigers, is full of popular misconceptions, but was much read at the time and so gave rise to the myth of the Anaconda of Ceylon.

Common names: yellow anaconda, Paraguayan anaconda.
Eunectes notaeus is a non-venomous boa species found in South America. No subspecies are currently recognized.

Description
Adults are not as large as the green anaconda, E. murinus, but nevertheless grow to an average of 10 to 12 feet (3.0 to 3.7 m) in length. The maximum size is almost certainly larger. Females are larger than males.

The color pattern consists of a yellow, golden-tan or greenish-yellow ground color overlaid with a series of black or dark brown saddles, blotches, spots and streaks.

Geographic range
Found in southern South America in eastern Bolivia, southern Brazil, Paraguay and northeastern Argentina. In Argentina it is found in the provinces of Corrientes, Chaco, Entre Rios, Formosa, Misiones and Santa Fe. The type locality given is "Paraguay River and confluents."

Habitat
Prefers mostly aquatic habitats including swamps, marshes, and brush covered banks of slow moving rivers and streams.

Feeding
These snakes were studied in regularly flooded areas in the Pantanal region of southwestern Brazil. The data were directly observed from predatory instances, analysis and examination of gut and waste contents and affirmations by local residents and other researchers. These indicate that the species is a generalist feeder. The prey list analyzed and other evidence suggests that E. notaeus employs both "ambush predation" and "wide-foraging" strategies. The snakes forage predominately in open, flooded habitats, in relatively shallow water; most predation instances occur from June to November, when flooded areas noticeably dried out. Wading birds are, at the certain times, the most common prey. They have also been known to prey on fish, turtles, small-sized caimans, lizards, birds eggs, small mammals and fish carrion. The prey to predator weight ratio is often much higher than those known for other types of boids.

Captivity
As captives they have a reputation for being unpredictable.

Giant anaconda

The green anaconda, Eunectes murinus, is the largest anaconda species. Females are bigger than their male counterparts.

Reports of giant anaconda date back as far as the discovery of South America when sightings of snakes upwards of 11 meters (33.5 ft) began to circulate amongst colonists and the topic has been a subject of debate ever since among cryptozoologists and zoologists. Anacondas normally only grow to size of 6 metres (20 ft), and 250 kilos in weight, but tales of truly gigantic specimens persist. Indeed, although some python species can grow longer in length, the anaconda, particularly the Green Anaconda, is the heaviest and largest in terms of diameter of all snakes, and is often considered the biggest extant snake in the world. It is not uncommon for a fully grown anaconda to attack and kill a jaguar or crocodile. Yet, despite the snake's large size, no specimens above the size of 35 feet (11 m) have been captured, and anacondas of this proportion are considered cryptids.

The first recorded sightings of giant anacondas were from the time of the discovery of South America, when early European explorers entered the dense jungles there and claimed to have seen giant snakes measuring up to 60 feet (18 m) long. Natives also reported seeing anacondas upwards of 50 feet (15 m) to 60 feet (18 m) It is unquestionable that anacondas above 30 ft (9.1 m) in length are rare; the Wildlife Conservation Society has, since the early 20th century, offered a large cash reward (currently worth US$50,000) for live delivery of any snake of 30 feet (9.1 m) or more in length, but the prize has never been claimed despite the numerous sightings of giant anacondas. In a survey of 1,000 wild anacondas in Venezuela, the largest captured was 17 feet (5.2 m) long, far short of the length required.

A specimen measured in 1944 exceeded this size when a petroleum expedition in Colombia claimed to have measured an anaconda which was 37.5 ft (11.4 m) in length, but this has never been proven. Scientist Vincent Roth also claimed to have shot and killed a 10.3 metres (34 ft) specimen, but like most other claims, this has never been proven. Another claim of an extraordinarily large anaconda was made by adventurer Percy Fawcett. During his 1906 expedition, Fawcett wrote that he had shot an anaconda that measured some 62 feet (19 m) from nose to tail. Once published, Fawcett’s account was widely ridiculed. Decades later, Belgian zoologist Bernard Heuvelmans came to Fawcett's defense, arguing that Fawcett's writing was generally honest and reliable. Historian Mike Dash writes of claims of still larger anacondas, alleged to be as long as 100-150 ft (30–45 m) — some of the sightings supported with photos (although those photos lack scale). Dash notes that if a 50–60 ft anaconda strains credulity, then a 150 ft long specimen is generally regarded as an outright impossibility.There could be a few legendary giants out there but these would have to be extremely rare, possibly reaching lengths of over 45 to possibly 50 feet (15 m).

Recently an anaconda measuring over six meters (more than 19 feet) and weighing nearly 200 kilos (440 pounds) was captured in the backyard of an abandoned house in Parana, Brazil.

Common names: dark-spotted anaconda, De Schauensee’s anaconda.
Eunectes deschauenseei is a non-venomous boa species found in northeastern South America. No subspecies are currently recognized

Geographic range
Found in South America in northeastern Brazil and coastal French Guiana. The type locality given is "probably collected on the island of Marajo at the mouth of the Amazon."

There is some debate regarding the maximum size of this species. Mehrtens (1987) states that the average adult length is 18 to 20 feet (5.5–6.1 m), with 25 feet (7.6 m) specimens being very rare. He sets a more conservative maximum at 23 feet (7.0 m). Estimates of 35 to 40 feet (11–12 m) are based on vague data and should be regarded with caution. In a study of 1,000 specimens captured in Venezuela, the largest was 17 feet (5.2 m) long and weighed 100 pounds (45 kg). Females are significantly longer than males, having the most conspicuous sexual dimorphism of all snakes.

The Wildlife Conservation Society has, since the early 20th century, offered a cash reward (currently worth US$50,000) for live delivery of any snake of 30 feet (9.1 m) or more in length. This prize has never been claimed. In any case, measuring a snake that is stronger than the person is not an easy task. It was found that two scientists independently measuring the same 12-foot (3.7 m) plus snake showed a variation of more than 20% in their results. The color pattern consists of olive green ground color overlaid with black blotches that run the length of the body. The head is narrow compared to the rest of the body, usually with distinctive orange-yellow striping on either side. The eyes are set high on the head and allow the snake to see out of the water when swimming without exposing its body.

Common names

Anaconda, common anaconda, water boa, green anaconda. Local names in South America include the Spanish term "matatoro," meaning "bull killer," and the Native American terms sucuri and "yakumama" in the Peruvian region of the Amazon, which means "mother of the water" in the language of the Amazonian Yakurunas or "water people".

Geographic range

Found in South America in countries east of the Andes, including Colombia, Venezuela, the Guianas, Ecuador, Peru, Bolivia, Brazil and on the island of Trinidad. The type locality given is "America."

Behavior

The primarily nocturnal anaconda species tend to spend most of its life in or around water. Anacondas are also sometimes known as the "Water Boa;" they spend more time in water than any of the boas. Because of its size being typically large it appears to be rather slow and sluggish when traveling on land. Completely the opposite in water however, anacondas are known to have the potential to reach incredibly high speeds in all depths of water levels. One tends to float atop the surface of the water with its snout barely poking out above the surface. When prey simply passes by or stops to drink, the hungry anaconda will snatch it using its jaws (without eating or swallowing it) and coils around it with its body. The snake will then constrict, tighten, and squeeze its coils until the anaconda has successfully suffocated and/or drowned its victim. Prey is suffocated, but never "crushed." The anaconda tightens only enough to stop its victim's breathing.

Feeding

Primarily aquatic, they eat a wide variety of prey, almost anything they can manage to overpower, including fish, birds, a variety of mammals, and other reptiles. Particularly large anacondas may even consume large prey such as tapir, deer, capybara, caiman, and sometimes crocodiles and jaguars, but such large meals are not regularly consumed. In addition, there have been many reports and documentaries on anacondas consuming humans.They employ constriction to subdue their prey. Cannibalism among green anacondas is also known, most recorded cases involving a larger female consuming a smaller male. Scientists cite several possible reasons for this, including the dramatic sexual dimorphism in the species and the possibility that female anacondas require additional food intake after breeding to sustain their long gestation period and the male simply being an opportunistic prey item, but the exact reason is not understood.

Reproduction

Senckenberg Museum exhibit of a capybara being devoured. This species is solitary until the mating season, which corresponds to the rainy season, can last for several months, and usually takes place from April to May. During this time, males must find females. Typically, female snakes will lay down a trail of pheromones for the males to follow, but it is still unclear how the males of this species track a female's scent. Another possibility is that the female releases an air-borne stimulant. This theory is supported by the observation of females that remain motionless while many males move towards them from all directions. The male anacondas also frequently lick the air to sense chemicals that signal the presence of the female.[citation needed] In any case, many males often find the same female. Although it may not be necessary for there to be more than one male, this results in odd clusters, referred to as "breeding balls," in which up to 12 males wrap around the same female and attempt to copulate. The group could stay in this position from two to four weeks. This ball acts as a slow-motion wrestling match between the males; each one fighting for the right to mate with the female. During mating, males make use of their spurs to arouse the female. They aggressively press their cloacal regions hard against the female body while continuously scratching her with their spurs. This can produce a scratching sound. Mating approaches its climax when the stimulus of the males' spurs induce the female snake to raise her cloacal region, allowing the cloacae of the two snakes to move together. The male then coils his tail, surrounding the female and they copulate.[citation needed] The strongest and largest male is often the victor. However, females are physically much larger and stronger and may decide to choose from among the males. Courtship and mating occur almost exclusively in water. Mating is followed by a gestation period that lasts approximately 6 months. The species is ovoviviparous, with females giving birth to live young. Litters usually consists of 20-40 offspring, although as many as 100 may be produced. After giving birth, females may lose up to half their weight. Neonates are around 70-80 cm long and receive no parental care. Because of their small size, they often fall prey to other animals. Should they survive, they grow rapidly until they reach sexual maturity in their first few years, after which their rate of growth continues at a slower pace.

Captivity

Anacondas, like other snakes and most other reptiles, can quite easily adapt to a change in the climate, environment, and near surroundings when necessary. The reasons for an anaconda's needing to adapt can vary. They may need to adapt to adjust to changes in the availability of food, and any diseases they may be exposed to in new surroundings. An anaconda might also have to adjust to changes in temperature and humidity. Changes in temperature could drastically affect the snake because it is ectothermal, and relies on its environment to control its temperature. If the temperature of its surroundings increases, a snake will do everything possible to prevent its body from over-heating, and if it decreases, it will attempt to lie in heated areas to help maintain its normal temperature. Anacondas, like all other snakes, control and regulate their body temperatures by changing the amount of surface of their skin that is exposed to the sun. If the terrarium, location or "tank" where a reptile is kept, is uniformly heated producing what is known as "the greenhouse effect", then the snake could possibly die from over-heating (hyperthermia). The humidity of its surroundings might also be slightly different than the humidity to which the snake was previously accustomed. This could, potentially, drastically alter its shedding cycle. The obstruction of this cycle is extremely dangerous. The hindrance of an anaconda's shedding cycle most often causes retention of eye caps. Due to these conditions and emotions of the snake, anacondas are known for their aggressive disposition when being held in captivity.