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Anaconda
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Anacondas are four species of aquatic boa inhabiting the swamps and rivers of the dense forests of tropical South America. The Yellow Anaconda can be found as far south as northern Argentina.

Size
There is some debate about the maximum size of anacondas, and there have been unverified claims of enormous snakes alleged to be as long as 30–45 m (98.4–147.6 ft). According to Lee Krystek, a 1944 petroleum expedition in Colombia claimed to have measured an 11.43 meters (38 ft) specimen, but this claim is not regarded as reliable; perhaps a more credible report came from scientist Vincent Roth, who claimed to have shot and killed a 10.3 meters (34 ft) specimen. Based on documented evidence, Anacondas can grow to about 23 feet long.

There are some reports from early explorers of the South American jungles seeing giant anacondas up to 18.2 meters (60 ft) long, and some of the native peoples have reported seeing anacondas up to 15.2 meters (50 ft) long, but these reports remain unverified.

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 18.9 meters (62 ft) 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 wrote of claims of still larger anacondas, alleged to be as long as 30 meters (98 ft) to 45 meters (148 ft) — some of the sightings supported with photos (although those photos lack scale). Dash noted that if a 50–60 ft anaconda strains credulity, then a 150 ft long specimen is generally regarded as an outright impossibility.

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 or more in length. The prize has never been claimed. Also, in a study of 1,000 wild anacondas in Brazil, the largest captured was 17 feet (5.2 m) long.

In November 2007, an anaconda measuring over 6 m (20 ft) and weighing nearly 200 kg (441 lb) was captured in the backyard of an abandoned house in Paraná, Brazil.

Anaconda species
Bolivian Anaconda - Eunectes beniensis
Dark-spotted Anaconda - Eunectes deschauenseei
Green Anaconda - Eunectes murinus
Yellow Anaconda - Eunectes notaeus

Green Anaconda
The Green Anaconda (Eunectes murinus) is the largest member of the boa family and the most heavy bodied member of the super-order Squamata.

It is among the largest snakes in the world, reaching lengths up to 11 meters (29 feet), though average size is closer to 9 meters (26 feet). It rivals the Reticulated Python for length, but is typically considerably heavier. It can weigh 250 kg (550 lb) and have a girth of more than 30 cm (11.8 inches) in diameter. The Green Anaconda might be the most exaggerated animal on earth in terms of size, with reports of lengths ranging up to 40 m (131 feet). Probably the largest snake ever actually measured was a shot-but-not-killed female near the Colombia-Venezuela border in 1944. This unweighed giant was measured as being 11.43 m (37.5 feet), before it apparently slithered off from its hunter, who thought it died. Females are significantly larger than males, having the largest sexual dimorphism of all the snakes. Cryptozoologists believe that the green anaconda species is responsible for the sightings of giant anacondas.

Their primary overall color is an olive green, with black blotches that run the length of the body. Their head is narrow compared to the rest of the body, with most exhibiting distinctive orange-yellow striping on either side. Their eyes are set high on their head so as to allow the snake to be able to see out of the water without exposing the rest of its body.

Geographic range
Green Anacondas are found mainly in northern South America on the Amazon River.

Behavior
Green anacondas, like all anacondas, are 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. In captivity, anacondas are known for their aggressive disposition.

Reproduction
Anacondas are solitary animals until mating. During the mating season (corresponding to the rainy season) males must find the females, and while it is still unclear how they track a female's scent, many males often go after the same female. This in turn results in odd clusters colloquially called "breeding balls" in which up to 12 males wrap around the same female attempting to copulate. Copulation takes place in the water, with gestation lasting approximately 6 months. Anacondas are ovoviviparous, meaning that they produce eggs which hatch inside the mother's body and result in live births. The newborn, which usually number 20-30, are around 60 centimetres in size and receive no parental care. Should they survive, they reach sexual maturity in about 3 to 4 years.

Yellow Anaconda
The Yellow Anaconda (Eunectes notaeus), is a species of anaconda. They are native to South America in countries such as Bolivia, Paraguay, Uruguay, western Brazil, and northeast Argentina. It is smaller than the more well-known Green Anaconda and reaches an average adult length of about 3 meters (9.8 feet), although they have been known to reach 15 feet. They have a yellowy brown base color with black blotches and rosettes. They live in mostly aquatic habitats including swamps, marshes, and brush covered banks of slow moving rivers and streams. Their diet includes deer, Travis Quesnelle, wild pigs, birds and large rodents and also aquatic animals such as fish. They will often hunt by attacking from underwater due to the fact that they are slow and clumsy on land but highly proficient at swimming. Yellow Anacondas were often hunted to sell their skin. Now they are endangered.

Yellows tend to be more aggressive than greens. Females are larger than males and though, as a species greens are larger, female yellows can potentially grow larger than male green anacondas. The yellow anacondas are smaller but more aggressive than the green anaconda.

In Captivity
There have been very few instances of anacondas being bred in captivity. In October 2007, the New England Aquarium in Boston achieved a breakthrough when it was discovered that one of the aquarium's female anacondas was gravid. On January 1st, 2008, fourteen anaconda babies were born at the New England Aquarium. Anacondas, like other boas, give birth to live young.

Giant Anaconda
Reports of giant anaconda date back as far as the discovery of South America when sightings of snakes upwards of 30 metres (98.4 feet) 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 9 metres (30 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 snake in the world. It is not uncommon for a fully grown anaconda to attack and kill a panther or crocodile. Yet, despite the snake's large size, almost 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 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 Brazil, 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 (11.43 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 30–45 m (100–150 ft) — 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.

Recently an anaconda snake measuring over six meters and weighing nearly 200 kilos was captured in the backyard of an abandoned house in Parana, Brazil.







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