Interior, Planos De Casas De 3 Dormitorios was posted June on this site by Aniesha.net. More over Planos De Casas De 3 Dormitorios has viewed by 66766 visitor.
Interior, Medidas De Muebles En Planta was posted June on this site by Aniesha.net. More over Medidas De Muebles En Planta has viewed by 19933 visitor.
Interior, Planos De Baños was posted June on this site by Aniesha.net. More over Planos De Baños has viewed by 92207 visitor.
Interior, Decoracion Cuartos De Baño Modernos was posted June on this site by Aniesha.net. More over Decoracion Cuartos De Baño Modernos has viewed by 18350 visitor.
Interior, Catalogo Muebles Cocina Pdf was posted June on this site by Aniesha.net. More over Catalogo Muebles Cocina Pdf has viewed by 59259 visitor.
Interior, Baños Modernos Chicos was posted June on this site by Aniesha.net. More over Baños Modernos Chicos has viewed by 95458 visitor.
Interior, Cocina De Restaurante was posted June on this site by Aniesha.net. More over Cocina De Restaurante has viewed by 92807 visitor.
Interior, Como Diseñar Una Silla Pdf was posted June on this site by Aniesha.net. More over Como Diseñar Una Silla Pdf has viewed by 15351 visitor.
Interior, Gradas De Casas was posted June on this site by Aniesha.net. More over Gradas De Casas has viewed by 80247 visitor.
The Javan wart snake is found on the coastal regions of India and Ceylon, and also across the Indo-Australian islands as far as the Solomons. It originated in India.
The Javan wart snake lives in the brackish zone of rivers, streams, and estuaries, and it sometimes swims short distances into the sea. It is also found near washed out banks.
The Javan wart snake has a muscular body and the male grows up to a length of five feet. The female is usually bigger and more powerfully built, with a length of up to eight feet. The top side of the snake's body is brown in color, and its sides and belly are pale yellow. The skin of the Javan wart snake is loose and baggy, with small rough scales. The scales are formed adjacent to each other and they do not overlap. On each scale, there is a sharp triangular ridge. The ventral scales of this snake are of the same size and shape as the other scales, unlike other types of snakes that often have enlarged ventral scales.
The shape of the snake's snouted head is flat and broad, with nostrils located at the top side of its head, giving this snake a boa-like appearance, although the width of the snake's trunk is identical to its head. The snake also has a short and mobile tail.
The Javan wart snake bears live young, about 20 to 30 offspring at one time. It has amniotic eggs, which are retained in the oviducts of the snake and are fertilized internally. The young snakes are semi-terrestrial, until their baggy skin is fully developed. This is because the baggy skin restricts them from moving efficiently on land. Besides a difference in size, the young can also be distinguished by the irregular, longitudinal blotches on their skin. These blotches fade over time, and eventually disappear when the adult stage is reached.
The Javan wart snake usually hides in the daytime and becomes active at night. Sometimes it will forage both during the day and at night. The snake captures its prey by folding its body around it, using its prehensile tail and the sharp scales to ensure a firm grip. The Javan wart snake rarely comes onto land. Their baggy skin is developed for agility under water and restricts them from traveling efficiently on land. Most of the time, the snake stays under the water surface, and it can do so for up to 40 minutes continously. When it need to breathe, the snake floats to the water surface and position its nostrils above water for 15 to 20 seconds.
The Javan wart snake is a carnivore. It feeds primarily on fish and other aquatic animals, but will sometimes feed on frogs. An interesting fact about this snake is that it does not bulge after feeding like other snakes do. Its body remains slack all the time because its skin is so loose and baggy.
They are easily aggravated. Although they are not venomous, their recurved teeth break off easily and are left inside one's flesh if a person is being bitten, thus creating unpleasant wounds.
The Javan wart snake is becoming increasingly rare. This is indicated by the fact that they are now seldom offered for sale. One reason for their scarcity is that they have been captured in large numbers because their skin is used for making leather goods. The other reason is that an effective and successful method of breeding is still not availiable yet.
Whooper swans (Cygnus cygnus) have an extensive geographic range and can be found within the boreal zone in Eurasia and many nearby islands. Boreal conditions often include cold winters, short summers, and dramatic seasonal temperature variations. Whooper swans breed in countries such as Iceland, Ireland, and Great Britain and migrate in the winter to countries such as China, Korea, and Japan. Some migratory populations can be found in India and western North America. (Birdlife International, 2012; Brazil, 2003)
Whooper swans breed and set up nests along the banks of freshwater lakes, pools, shallow rivers, marshes, bogs, and swamps. They prefer habitats with emergent vegetation, which may provide additional protection for nests and newborn cygnets. In Iceland, they are commonly found in habitats ranging from sea-level to an elevation of 700 m. Non-breeding pairs of swans can be found near sheltered estuaries, lagoons, and shallow bays. Migrating whooper swans fly at altitudes of 500 to 1,700 m when crossing oceans, but often prefer flying at lower levels to allow for frequent breaks between flights. Near the British Isles, migrating whooper swans have been recorded reaching heights above 8,000 m. (Brazil, 2003; Gardarsson and Skarphedinsson, 1984; Laubek, et al., 1999; Pennycuick, et al., 1996)
Both male and female whooper swans have white plumage with black webbed feet and legs. Their beaks are orange-yellow at the base with a black tip. The markings on their beak can be used to differentiate between individuals. In the spring and summer, adults may develop dark neck plumage due to their iron-rich environment. Juveniles have downy grey-brown plumage with a pink and black tipped beak. Adult whooper swans are large birds, with an average length of 1.4 to 1.65 m and a wingspan of 2.05 to 2.75 m. Male weights range from 7.4 to 14 kg with an average of 9.8 kg, which is much heavier than the female weight range of 8.2 to 9.2 kg. The highest recorded mass was 15.5 kg for a wintering male swan in Denmark. Aside from body mass, males can also be differentiated from females by their longer and thinner necks. A close relative of whooper swans are the smaller, shorter-necked Bewick swans. These swans can be differentiated by beak color. Whooper swans have more orange-yellow beak markings while Bewick swans have more black markings. (Brazil, 2003; Dunning, 1992; Rees, et al., 1997)
Whooper swans are monogamous and form lifelong pairs. In some cases, individuals will find a new mate if their partner dies. Whooper swans can be territorial during the breeding season. Rivals sometimes fight savagely by beating their wings and, depending on their location, either ground staring or head-plunging. Courtship displays can begin in the winter, but most occur in the summer. Males and females often bob their heads up and down as a greeting and then, with bodies facing each other, turn their necks from left to right as they beat their wings fervently. Before copulation occurs, pre-copulation displays are short and include head dipping and thrusting of their neck and chest into the water. Copulation is short and lasts around a minute. During copulation, the male grasps the female's nape. Certain pairs participate in post-copulation preening. (Brazil, 2003)
Whooper swans breed once a year, their breeding season begins in late April and early May. The earliest eggs are laid in late April, but the majority of eggs are laid in May. Whooper swan eggs are large and elliptical with an off-white coloration. Older eggs may become stained and turn brown after several days due to nest conditions and iron-rich waters. A single clutch is laid per year. Clutch sizes depend on the age of the pair and the resource availability of their chosen breeding site. Younger couples tend to be inexperienced and lay smaller clutches. Nests are often situated on a large mound near a body of fresh water with riparian vegetation nearby for protection. Incubation lasts around 30 to 32 days and hatching begins from June to early July. Not all pairs lay eggs, and not all eggs hatch. Cygnets are precocial and are covered with down feathers when they hatch. They leave the nest 2 to 3 days after hatching. After three months, chicks begin to fledge and are able to fly at 78 to 96 days. Fledglings become independent after a year and become sexually mature after about 4 years, which is an uncommonly long time. Cygnet growth rates are impacted strongly by habitat quality and food availability. (Black, 1996; Brazil, 2003)
After the first egg is laid, the female's main priority is incubation and the male's priority is protecting the nest and the surrounding territory. Swans have long incubation periods. Males rarely incubate the eggs, but they vigilantly guard the nest by remaining within 50 to 100 m from the nest. When females take incubation breaks to feed, the eggs are able to maintain a constant temperature due to their larger size, which helps minimize heat loss. The length of incubation breaks increase as eggs mature, and incubation stops completely several days before hatching. The first few days after hatching, cygnets remain close to the nest where they are taken care of by the female. Unlike their close relative, trumpeter swans, whooper swans do not carry their young on their backs. Mortality rates are high for cygnets due to susceptibility to cold weather, predators, and inadequate feeding. Parents help cygnets feed and remain close to them in the early stages of development. Whooper cygnets stay within shaded areas near their parents until fledging. Parental care declines as cygnets grow older and parents begin to spend less time with their heads above water and more time feeding. In general, males keep a vigilant watch before hatching and females take over that role during fledging. After fledging and before independence, the distance between cygnets and parents increases as the young become bolder and more adventurous. However, broods remain together even after fledging. Interestingly, if an early freeze occurs and cygnets are not yet able to fly, parents may leave their brood behind. This often results in the cygnets' death due to the absence of parental guidance. Cygnets tend to migrate with their parents until one year of age, and then parents restart the reproduction cycle. (Brazil, 2003)
Adult whooper swans can live for decades. They have a small annual mortality rate once they are past the first few weeks after hatching. One common cause of death occurs when wild whooper swans decide to continue feeding off of agricultural cereal grains instead of migrating south to feed on aquatic vegetation. This shift in behavior has resulted in whooper swans freezing to death. However, the greatest cause of adult and juvenile deaths is the result of flying accidents. (Brazil, 2003)
Whooper swans are territorial during the summer but social during the winter. Whooper swans can be found living in flocks near wetlands. Larger flocks of more than 40 individuals are more common from October to November, whereas smaller flocks of fewer than 30 individuals are more common from January to early spring. There is a social hierarchy with larger families at the top, monogamous pairs in the middle, and unpaired individuals at the bottom. Dominant birds can feed for the longest period of time, and individuals often seek to join flocks for added protection. Aggressive males may also cause one family to be more dominant over another family of equal size. Cygnets rarely initiate flight, but they participate in pre-flight signaling to communicate with their parents. (Brazil, 2003)
There is little information available regarding the territory size defended by whooper swans, although some estimates suggest that it is as low as 0.7 km2, while others suggest it is as high as 5.7 km2. Breeding pairs generally do not share a territory, however, in some circumstances several pairs have been found sharing the same small body of water. (Brazil, 2003)
Whooper swans use several pre-flight signals to indicate that it is time to leave a certain area. Common movements include 'head pumping', increased four-syllabic calling, and wing flapping. Flocks continue to increase signaling to build excitement and allow synchronization to occur during take-off. Shortly after landing, whooper swans sometimes participate in greeting or triumph ceremonies, which include head bobbing, calling, and wing flapping. Due to the closeness of these interactions, greeting and triumph ceremonies can easily transition to either sexual or aggressive interactions. Aggression toward others can be displayed by a combination of ground staring, where the neck is arched and wings are spread slightly, bow-spitting, where the neck is held forward, and carpal flapping, where the wings flap vigorously. In the case of conspecific competition, a 'water-boiling' display may occur, in which both swans outstretch their wings before physical attacks are initiated by both parties. (Brazil, 2003)
Whooper swans feed in shallow bodies of water and consume aquatic plants and roots. Cygnets feed on small insects and other invertebrates to meet their high protein requirements for proper growth and development. In shallow fresh waters, whooper swans use their webbed feet to dig in the mud and then dip their head into the water to feed on shallow roots and tubers. Parents also help cygnets feed by stirring up the water column to make aquatic vegetation more accessible. Whooper swans can also feed in terrestrial habitats or near saltwater tidal environments. In freshwater systems, their foraging activity peaks in the morning and afternoon. Whooper swans that prefer feeding in saltwater systems have foraging peaks during the time gap between morning and afternoon. Feeding is harder during high tide, so whooper swans prefer to rest at high tide and feed during low tide. Terrestrial foraging behaviors are affected by day length, temperature, and safety. When days are short, cold, and dark, whooper swans are less energetic and forage less in comparison to days that are longer, warmer, and brighter. In areas with farming, such as Denmark and northern Germany, whooper swans feed on crops during the winter. In central Scotland, swans that rely on agricultural land feed on leftover grains in autumn and then feed on grass from mid-winter until spring. The majority of whooper swans fed on freshwater roots, stems, and leaves and the remaining minority feed on mussels in shallow marine waters. (Brazil, 2003)
Resting whooper swans are able to curl up on the ground to reduce exposure to cold climates while still maintaining the ability to open their eyes easily to spot predators. Predators often attack clutches by stealing one egg at a time when parents take incubation breaks to feed. Once whooper swans reach their adult size, the threat of predation decreases, and most predation occurs when cygnets are young and rely heavily on parental protection. Due to their larger size, whooper swans are not very agile on land and often retreat into the water to be safe from terrestrial mammalian predators. (Brazil, 2003)
Large quantities of biomass are lost when whooper swans feed on their preferred submerged macrophyte, fennel pondweed; this stimulates the pondweed to grow at intermediate depths. In contrast, their less favored plant, claspingleaf pondweed grows at either shallow or deep depths. As such, whooper swans play a key role in impacting plant community structures. There have also been reported cases of nest parasitism by greylag geese and red-crested pochard birds that lay their eggs in whooper swan nests. (Brazil, 2003; Kiorboe, 1980; Sandsten and Klaassen, 2008)
Whooper swans have been hunted in the past but are generally unafraid of humans and will take food directly from a human's hand. This level of approachability occurs mainly during the winter when food is scarce. Their friendliness has drawn crowds of people and tourists who come to admire their beauty and signature whooping calls. (Brazil, 2003)
Some whooper swans prefer to feed on crop plants due to the higher nutritional value obtained from eating these foods. This adversely affects the farmers whose crops may be damaged. In addition, the pathogenic avian influenza virus H5N1 was isolated from the eyelids of a whooper swan during the 2010 H5N1 outbreak in Japan. Whooper swans are susceptible carriers of the disease due to their wide ranged migratory behaviors. (Brazil, 2003; Bui, et al., 2013)
Human activities that threaten whooper swans include hunting, egg poaching, and habitat degradation. There have been conservation efforts to preserve popular wetland sites from Iceland to China and laws that make hunting the swans illegal in Russia. Conservation efforts have been fruitful, as the status of the species is considered one of “least concern.” (Birdlife International, 2012; Brazil, 2003)
Birdlife International, 2012. "IUCN Red List of Threatened Species" (On-line). Cygnus cygnus. Accessed October 25, 2013 at http://www.iucnredlist.org/details/22679856/0.