ANACONDA-BIGGEST SNAKE ON EARTH

ANACONDA

         Eunectes murinus
The Green Anaconda, also known as the water boa. There is also the yellow Anaconda, Eunectes notaeus.


The name "Anaconda" comes from the Sri Lankan language, Sinhalese, which originally probably referred to the Reticulated python. No one is sure how this name came to represent a South American snake, unless these two snakes, Anaconda and Python, were mistaken as the same species. Both snakes are swimmers and two of the largest snakes in the world.

The Tamil word for Anaconda is "Anaikolra" which means "elephant killer". The early Spanish settlers referred to this snake as "Matatoro" or "bull killer".
Classification:
Phylum - Chordata
Class - Reptilia
Order - Squamata
Family - Boidae
Circadian Cycle - Nocturnal


Physical Characteristics
The Anaconda is considered the biggest snake in the world. These snakes may reach lengths of over 29 feet. There are many exaggerated stories about anacondas being much longer, but they cannot be confirmed.



The Anaconda is the heaviest snake, but it may or may not be the longest.The Reticulated python rivals the Anaconda for the longest snake. A 20-foot Anaconda will weigh more than a 33-foot python. The Anaconda can weigh 550 pounds or more, but will usually top out at a few hundred pounds. These snakes can measure more than 12 inches in diameter. The female typically outweighs the males.

The Green Anaconda is dark green in color with black oval patches on its back. This drab pattern blends the snake in well with the wet, dense vegetations of its habitat. The sides have similar spots with yellow centers. The Yellow Anaconda is true to its name and is mostly yellow with similar black spots. The scales of the yellow and black underside of the lower tail on these Anacondas have a particular pattern which is unique to each snake. It's a form of identification, like a human fingerprint.

Snakes have a cavity called a cloaca which is where the intestinal and genitourinary tracks empty. Anacondas have spurs on either side of the cloaca. The cloaca of the Anaconda has a gland which emits a foul-smelling musk. This brownish musk is quite poisonous to small organisms. This may prevent ticks and leeches from attaching themselves here. When Anacondas are out of the water for long periods of time they usually become infested with ticks.

The Anaconda come equipped with a large head and a thick neck. Its eyes and nostrils are positioned on the top of the head, enabling the Anaconda to breathe and to see its prey while its stocky body lays submerged under water. The extremely muscular Anaconda is a constrictor and is not poisonous; however, it still has teeth and powerful jaws that it utilizes to clench onto its prey. It grabs its victim and pulls it underwater, drowning the prey.

Range: Neotropical
The Anaconda is found in the Guianas, throughout tropical South America, east of the Andes and mainly in the Amazon and Orinoco Basins The Yellow Anaconda can be found as far south as Argentina.

Habitat
The various biomes where Anacondas are usually found are tropical rainforests, savannas, grasslands, scrub forests, and deciduous forests. The Anaconda prefers to be in the water, but they do enjoy spending some time on land in shallow caves by the water's edge, or in riverbank trees to bask in the sun.

On land they can become tick-infested and they cannot move as quickly as they do in water. In water, they can stay completely submerged for 10 minutes. They often lay submerged waiting for prey. They are agile swimmers but sometimes prefer to let the river's current carry them downstream with only their nostrils above the watery surface. Once they are satisfied with the change in scenery, they simply drift to the river's edge.

Anacondas are more often found in swamps and calmer waters than in swift-moving rivers.

Diet -- Carnivorous


They typically feed on large rodents, tapirs, capybaras, deer, peccaries, fish, turtles, birds, sheep, dogs and aquatic reptiles. They have been known to occasionally prey on jaguars and attacks on humans can be confirmed, although this is rare. Younger Anacondas feed on mice, rats, chicks, frogs and fish.



Anacondas are usually coiled up in a murky, shallow pool or at the river's edge. They wait to ambush their unsuspecting prey when they come down for a drink. Anacondas bite their prey with their sharp teeth, hold on with their powerful jaws and pull them under water. The victim may drown first or it may be squeezed to death in the Anaconda's muscular coils. Anacondas, true to the Boa family, constrict their hapless victims to death. The snake squeezes tighter each time its prey breathes out, so the prey cannot breath in again. Suffocation does not take long. Anacondas swallow their prey whole, starting with the head. This is so the legs fold up and the prey goes down smoothly. The Anaconda can swallow prey much bigger than the size of its mouth since its jaw can unhinge and the jawbones are loosely connected to the skull. while the snake eats, its muscles have wave-like contractions, crushing the prey even further and surging it downward with each bite.

The Anaconda has a very slow-acting digestive system. After a big meal the Anaconda will rest for several days while digestion occurs. Many Anacondas will not eat again for several weeks or even months, depending on the size of the last meal. One captive Anaconda is on record for fasting over two years!

Reproduction

Normally the Anaconda is a solitary creature that stays within its own hunting area. This changes with the onset of the rainy season. Courtship can last for several months with this species. During this time, the female in breeding condition gives off pheromones, a chemical scent, which is tracked by nearby males. Some scientists believe the females lay down a pheromone trial which the males follow. Others believe that her scent is an air-borne chemical emission. This latter theory is supported by the fact that the female is not very active during this time and males come to her from all directions. Males have also been observed flicking the air to pick up the chemical presence.

Courtship and copulation usually take place in the water. The male presses his body to the female and rests his head on her neck. His tongue flicks and his spurs become erect. The spurs rub against the female's vent region which encourages her to copulate. As he presses his cloacal region against hers, his spurs make a scratching sound. Copulation is complete when the female raises her cloacal region to meet the male's. The male holds her against him tightly by wrapping his tail and lower body around her.

The gestation for the Anaconda is approximately 6 months. Anacondas are viviparous, bearing live young. A typical litter may consist of 20-40 babies, but a female can birth up to 100 neonates. These babies are usually 2 feet long a birth. Many newborn Anacondas refuse food for the first few months of life. Because of their small, newborn stature, many Anaconda babies are prey for other animals.

Within hours after birth, Anaconda neonates can swim, hunt and care for themselves. Baby Anacondas grow rapidly until they reach sexual maturity at the age of 3-4 years. They do continue to grow after this time, but at a slower rate.

Life Span



Anacondas can live into their thirties.

Special Adaptations



The Anaconda has eyes high on its head so that it can stay camouflaged underwater while watching and waiting for its prey. Its nostrils are positioned there as well, so that it can breathe easily while almost completely underwater. Another form of camouflage is the Anaconda's color pattern of dull green with black spots. This blends in with the dense vegetation of its habitat and also with the murky water that Anacondas love.

At Nashville Zoo at Grassmere
If you would like to see one of the world's largest snakes, come on out to the Park! Our Anaconda measures 18 feet long! This amazing creature is housed in our Unseen New World exhibit along with some other very creepy and very crawly critters! We hope to see you soon.


Conservation
At present, all South American countries prohibit trade regarding the Anaconda. However, some of these countries will allow live export for zoos and research in a limited capacity.

The greatest threat to the Anaconda is man. Most local people kill these snakes on sight, out of the fear that they are man-eaters. In most instances, if an Anaconda senses humans in the area, it will retreat in another direction. Human death by Anaconda is quite rare. Habitat destruction is another problem that the Anaconda faces.

There is much to learn about the Anaconda. Presently, CITES, PROFAUNA and The Wildlife Conservation Society jointly are conducting the first field study of the Anaconda. Hopefully many questions will be answered by this study.

LINK
http://www.extremescience.com/BiggestSnake.htm
http://en.wikipedia.org/wiki/Anaconda