Anacondas

Eunectes
Green anaconda, E. murinus
Scientific classification
Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrata Class: Reptilia Order: Squamata Suborder: Serpentes Family: Boidae Subfamily: Boinae Genus: Eunectes Wagler, 1830
Synonyms
Eunectes - Wagler, 1830[1]

Eunectes is a genus of non-venomous boas found in tropical South America, commonly called anacondas. An aquatic group of snakes inhabiting swamps and rivers, its members include some of the largest snakes in the world. Despite this, little was known about them until recently. The name Eunectes is derived from the Greek word Eυνήκτης, which means "good swimmer." Three species are currently recognized.^[2]

Contents 1 Physical Description 2 Common names 3 Location 4 Feeding habits 5 Behavior 6 Captivity 6.1 Environmental requirements 7 Reproduction 8 References 9 External links

Physical Description

There are some debates about the maximum size of these snakes. Mehrtens (1987) states that the average adult length for the green anaconda, E. murinus, is 18 to 20 feet (5.5–6.1 m), with 25 feet (7.6 m) specimens being very rare. He sets a much more conservative maximum at 23 feet (7.0 m). Estimates of 35 to 40 feet (11–12 m) (see Giant anaconda) are based on vague data and should be regarded with caution.^[3] 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).^[4]

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. This prize has never been claimed yet.^[5] In any case, measuring a snake that is stronger than a 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.^[6]

Common names

Local names in South America include the Spanish term "matatoro," meaning "bull killer," and the Native American terms sucuri and "yakumama."

A possible origin for the common is perhaps an alteration of the Sinhalese word henakandaya, meaning 'whip snake' or anaconda is the Tamil anaikondran, meaning "elephant killer", or anaikkonda, meaning "having killed an elephant".^{[citation needed]} The name that was first used in English to name a Ceylonese python, it erroneously was applied to a large South American boa, which is called in Brazil "sucuri". The word has no certain origin, and no snake name like it now is found in Sinhalese or Tamil. Another suggestion is that it represents Tamil. However, it is unclear how this name originated so far from the snake's native habitat; possibly this is due to its vague similarity to the large Asian pythons.

Location

Anacondas and other snakes of the Boinae subfamily are usually located in Madagascar, the Neotropics, the Papuan-Pacific Islands. It has also been proposed that a snake called the "New World Boa Constrictor" is not as close in relation to boine genera in the Neotropics than to boines parts of Madagascar.^[7]

Feeding habits

The yellow anaconda (Eunectes notaeus) were studied in regularly flooded areas in the Pantanal region of southwestern Brazil. The data directly observed from predatory instances, analysis and examination of gut and waste contents, and affirmations of local residents and other researchers indicate the snake to be not only carnivorous but also a generalist (one who has well understanding and proficiency that can be applied to a field). The prey list analyzed and other evidences support that the E. notaeus employs both "ambush predation" and "wide-foraging" strategies, meaning that it will eat the dead and alive. Yellow Anacondas claim to forage predominately in open, flooded habitats, in relatively shallow water; most predation instances occur from June to November, when flooded areas noticeably dry out. Wading birds, at the proper times, are the most common prey selection for this hungry reptile. Yellow Anacondas also tend to prey on fish, turtles, small-sized caimans, lizards, bird eggs, small mammals and fish carrion. This extremely large prey to predator weight ratio indicates its prey has a much lower weight than those known for other types of boids (the family of non-venomous, constriction snakes).^[8]

The green anaconda, however, is carnivorous, and will prey on any vertebrate within reach and swallow it. It is especially interested in other snakes, amphibians, fish, and mammals such as capybara. The smaller side of the species have been known to climb trees to attack and consume bird nests, while the larger of the specimens may, and usually do, prey on small deer, caimans, and peccaries. Few records show that there have been attacks on humans. However, no known deaths have been recorded. As all other snakes do, the green anaconda swallows its victim whole and, because their jaws are not hinged, they are able to swallow prey with a diameter larger than that of their mouths. Green anacondas usually swallow prey head-first, because this is the usual way the limbs tend to fold over. The mouth muscles of the snake then contract in waves as the swallowing process continues, crushing its prey with each surge forward. Their digestive system is slow-acting and it usually takes either days or weeks to digest the food. After every meal, anacondas might not eat for weeks or months.^[9]

Primarily aquatic, they eat a wide variety of prey, almost anything they can manage to overpower, including fish, birds, 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 eaten. In addition, there have been many reports and documentaries about 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.^[10]

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" and spends 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. Anacondas usually lay around in trees and attack its prey from above, and coiling around it, leaving it completely helpless and unaware of what had just happened. The dead carcass of the animal murdered in the attack is rarely crushed completely. The anaconda merely tightens only enough to stop its victim's breathing, and cutting off all airways. It is also known that the anaconda has the potential to shatter and crush all of the bones in its victim's body and often does this to the prey because it will remain and continue to move and squirm while the crushing of its bones, prevents and disables that from happening.^[11]

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 that of which the snake was previously used to. 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.^[12] Due to these conditions and emotions of the snake, anacondas are known for their aggressive disposition when being held in captivity.^[13]

Environmental requirements

One may reasonably maintain an average and acceptable temperature for the snake by the use of a simple heater and infrared light bulbs. Anacondas and other snakes must be exposed to ultraviolet(UV) radiation. This is exceptionally significant because the snake needs it to produce vitamin D₃ for further bone development in its body. Occasional exposure to light bulbs that emit UV radiation with proper wavelength, or better yet, the sun, is also necessary to maintain the positive heath of an anaconda. Optimum humidity can be difficult to maintain and research must be done on the snake to determine the correct level. A percentage of just less than 80% humidity must be maintained for caging an anaconda species from the tropical region, while a slightly less than 30% humidity must be maintained for a species of a desert region.^[14]

Reproduction

Green anacondas, like all snakes, reproduce sexually and fertilization occurs within the mother's body. Courtship lasts over several months in many cases and usually takes place from April to May. The female is thought to lay down a trail of pheromone, which attracts the male anaconda toward her. Another possibility is that the female releases air-borne stimulant. This theory is supported by the observation of the mating female; who remains motionless while many males gather and move towards her from all directions. The male anacondas also frequently lick the air to sense chemicals that signal the presence of the female.^{[citation needed]}

Although it may not be necessary for there to be more than one male, quite frequently the male snakes group together in what is known as a breeding ball, or sphere. This ball can consist of up to twelve males wrapped around one female snake. 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. The strongest and largest is often the victor. However, the female anaconda, naturally physically much larger and stronger, may decide to choose from among the males. Courtship and mating occur almost exclusively in water. The female green anaconda will be pregnant for about 6 months. Pregnant green anacondas also tend to feed during this time. In contrast, during breeding season males kept together tend to reject food.^{[citation needed]}

The male makes use of its spurs to arouse the female during mating.They aggressively press their cloacal regions hard against the female body while continuously scratching her with their spurs. This makes 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]}

This species is viviparous, giving birth to live young. A female anaconda can give birth to as many as a hundred young, though typically the size of the litter ranges from 20 to 40. The female may lose up to half of her pre-birthing weight after birth. The neonates are usually around 70-80 cm long at birth. Because of their small size they often fall prey to other animals. They grow rapidly until they reach sexual maturity in their first few years, after which their rate of growth continues at a slower pace.^[15]

References

External links

• Eunectes at the TIGR Reptile Database. Accessed 18 July 2008.
• Life history and conservation of the green anaconda (Eunectes murinus) at Anacondas.org. Accessed 18 July 2008.

---

No comments have been added.

Your name:
City:
Country:	USA UK India Pakistan UAE Saudi Arabia Germany Afghanistan Albania Algeria Andorra Angola Antigua Barbuda Argentina Armenia Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bhutan Bolivia Bosnia Herzegovina Botswana Brazil Brunei Bulgaria Burkina Faso Burma Burund Cambodia Cameroon Canada Central African Rep Chad Chile China Columbia Comoros Congo Costa Rica Croatia Cuba Cyprus Czech Republic DR Congo Denmark Djiboutil Dominica Dominican Rep Ecuador Egypt El Salvador Eq Guinea Eritrea Estonia Ethiopia Fiji Finland France Gabon Gambia Georgia Germany Ghana Greece Grenada Grenadines Guatemala Guinea Bissau Guinea Guyana Haiti Honduras Hong Kong Hungary Iceland India Indonesia Iran Iraq Ireland Israel Italy Ivory Coast Jamaica Japan Jordan Kazakhstan Kenya Kiribati Kuwait Kyrgyzstan Laos Latvia Lebanon Liberia Libya Liechtenstein Lithuania Luxembourg Macedonia Macau Madagascar Malawi Malaysia Maldives Mali Malta Mauritania Mauritius Mexico Micronesia Moldova Monaco Mongolia Morocco Mozambique Namibia Nauru Nepal Neth Antilles Netherlands New Zealand Nicaragua Niger Nigeria North Korea Norway Oman Pakistan Panama Papua New Guinea Paraguay Peru Philippines Poland Portugal Puerto Rico Qatar Rawanda Romania Russia Sao Tome Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Slovakia Slovenia Solomon Islands Somalia South Korea South Africa Spain Sri Lanka St Kitts_Nevis St Lucia Sudan Suriname Sweden Switzerland Syria Taiwan Tajikistan Tanzania Thailand Togo Tonga Trinidad and Tobago Tunisia Turkey Turkmenistan Tuvala UAE Uganda Ukraine Uruguay Uzbekistan Vanuatu Venezuela Vietnam Western Samoa Yemen Yugoslavia Zaire Zambia Zimbabwe
Your comments:
Security check * (Please enter the number into adjoining box)