Nature trail:

Three giant reptiles

Last week we took you on a journey into the world of reptiles and promised to bring you some more interesting info about this group of animals which has always brought mixed reactions from many people, not only due to their unappealing appearance but also their harmful behaviour, especially when it comes to species such as the snakes and crocodiles.

The inhabitants of the reptile world are numerous ,so today let's focus on three species that rank among the largest in this group.

Green anaconda

Komodo Dragon

A cousin of the reticulated python, South America's green anaconda is a member of the boa family. Even though the reticulated python can reach slightly greater length than it, many consider the green anaconda to be the largest snake in the world. Why? Because of its enormous girth which makes it almost twice as heavy. So, green anacondas are the largest (by weight) snakes in the world. They are also among the longest snakes in the world.

Green anacondas can grow to more than 29 feet (8.8 metres), weigh more than 550 pounds (227 kilograms), and measure more than 12 inches (30 centimetres) in diameter. And this is just the size of the male anacondas. The females are said to grow even bigger. Green anacondas are, as their name suggests, green in colour. They have black spots across their entire bodies that are unsymmetrical, forming perfect camouflage for the thick, dense forests that they live in. Spots on the sides of their bodies often have yellow centres.

Like all reptiles, green anacondas have scaly skin. Their skin is dry and somewhat thick. Green anacondas are very str ong and muscular, and they must be so in order to attack and kill large prey.

The huge green anaconda is however not the only one found in South America . There are other anaconda species, all smaller than the green anaconda such as the yellow, dark-spotted, and Bolivian varieties.

Where would you come across this humongous creature in South America? Generally in swamps, marshes, and slow-moving streams, mainly in the tropical rain forests of the Amazon and Orinoco basins. Green anacondas are very well adapted to living in the tropical rain forests of the Amazon River Basin. Since they are cold-blooded, year-round warm-temperatures help to keep their blood warm.

You may have seen them move about on land (on the electronic media or in films )and observed how cumbersome they are on land. Don't be fooled by it. They are stealthy and sleek in the water. As their eyes and nasal openings are located on top of their heads, the anacondas can lie in wait for prey while remaining nearly completely submerged in the water, like the crocodiles.

If you are wondering as to what kind of diet they eat to become so huge the answer is wild pigs, deer, birds, turtles, capybara, caimans, and yes, hold your breath, even jaguars!

Anacondas are nonvenomous constrictors, coiling their muscular bodies around captured prey and squeezing until the animal asphyxiates.(die or lose consciousness due to impairing normal breathing). Anacondas have jaws attached by stretchy ligaments which allow them to swallow their prey whole, no matter the size. After eating a large animal anacondas can wait weeks or months without food .

Anacondas are ovoviviparous, which means that the eggs hatch while still inside the mother. Female anacondas retain their eggs and give birth to two to three dozen live young. Baby snakes are about two feet (0.6 metres) long when they are born and are almost immediately able to swim and hunt. Their lifespan in the wild is about ten years. In 1997, the movie "Anaconda" was made. The film features a giant green anaconda that is being hunted by a snake hunter and a film crew. Watch the movie and you will learn more about this slithering reptile.

Komodo dragon

The largest living species of lizard the Komodo dragon (Varanus komodoensis), also known as the Komodo lizard is a member of the monitor lizard family (Varanidae). It is found in the Indonesian Islands of Komodo, Rinca, Flores, Gili Motang and Padar. Would you believe that this lizard can grow to a maximum length of three metres (10 ft) in rare

cases and weigh up to around 70 kilograms (150 lb)? Their unusual size has been attributed to island gigantism, since there are no other carnivorous animals to fill the niche on the islands where they live. As a result of their size, these lizards dominate the ecosystems in which they live.

Komodo dragons were first recorded by Western scientists in 1910.The Komodo dragon prefers to live in hot and dry places so they can be found in dry open grassland, savanna, and tropical forest at low elevations. It is most active in the day, although it exhibits some nocturnal activity. Despite its visible ear holes the Komodo dragon does not have an acute sense of hearing. It is only able to hear sounds between 400 and 2000 hertz. Its vision too is said to be poor at night even though it can see as far away as 300 metres (980 ft). According to scientists the Komodo dragon is able to see in colour, but as poor visual discrimination of stationary objects.

As with many other reptiles the Komodo dragon too uses its tongue to detect, taste, and smell stimul. It only has a few taste buds in the back of its throat. Its scales, some of which are reinforced with bone, have sensory plaques connected to nerves that facilitate its sense of touch. The scales around the ears, lips, chin, and soles of the feet may have three or more sensory plaques.Komodo dragons are generally solitary animals and get together only for breeding and eating . They are carnivores. The group behaviour of Komodo dragons in hunting is exceptional in the reptile world. They hunt and ambush prey including invertebrates, birds, and mammals. The diet of big Komodo dragons mainly comprise deer, though they also eat considerable amounts of carrion. There are reports of attacks on humans too from he area of West Manggarai Regency where they live in Indonesia.

Komodo dragons have been observed knocking down large pigs and deer with their strong tail. They are capable of running rapidly in brief sprints up to 20 kilometres per hour (12 mph), diving up to 4.5 metres (15 ft), and climbing trees proficiently when young through use of their strong claws. For shelter, the Komodo dragon digs holes that can measure from 1-3 metres (3-10 ft) wide with its powerful forelimbs and claws.

The female deposits about twenty eggs in abandoned megapode nests or in a self-dug nesting hole in September. The eggs are incubated for seven to eight months, hatching in April, when insects are most plentiful. As young Komodo dragons are vulnerable to attacks from other cannibalistic Komodo adults and predators they dwell in trees most of the time . They take about eight to nine years to mature, and are estimated to live for up to 30 years.

In the wild their range has contracted due to human activities and they are listed as vulnerable by the IUCN. They are protected under Indonesian law, and a national park, Komodo National Park, was founded to aid protection efforts.

Leatherback sea turtle

The leatherbacks are said to be the largest turtles on Earth, growing up to seven feet (two metres) long and exceeding 2,000 pounds (900 kilograms). Even though these turtles were once found in every ocean except the Arctic and the Antarctic, today their population is rapidly declining.

They rank as the most widely distributed reptile species and can be found in the Pacific, Atlantic and Indian Oceans . Even in Sri Lanka leatherback turtles can be seen in areas such as Induruwa, Kosgoda, Mavela, Usangoda, Ambalantota, Bundala and Yala when they come to nest on the beaches.

Leatherbacks undertake the longest migrations between breeding and feeding areas of any sea turtle, averaging 3,700 miles (6,000 kilometres) each way. Adult leatherbacks are known to travel as far north as Canada and Norway and as far south as New Zealand and South America.

They are called reptilian relics by scientists because they are the only remaining ones from a family of turtles that trace their evolutionary roots back to over 100 million years. Most sea turtles have hard, bony shells but the inky-blue shell of the leather backs are somewhat flexible and almost rubbery to the touch. There are ridges along the carapace which gives it a more hydrodynamic structure. Do you know that leatherbacks can dive to depths of 4,200 feet (1,280 metres)-deeper than any other turtle-and can stay down for up to 85 minutes?

Leatherbacks have the widest global distribution of all reptile species, and possibly of any vertebrate. They can be found in the tropic and temperate waters of the Atlantic, Pacific, and Indian Oceans Leatherbacks have an edge over their reptilian relatives,when it comes to maintaining body temperature.

They can retain warm body temperatures in cold water by using a unique set of adaptations which include large body size, changes in swimming activity and blood flow, and a thick layer of fat.Females come ashore during the breeding season to nest. They excavate holes in the sand to deposit around 80 eggs in the night. Once they fill up the nest they return to the sea leaving a large, disturbed area of sand that makes it difficult for predators to detect the nest .The eggs hatch out either male or female baby turtles depending on the temperature inside the nest. It is the temperature inside the nest that determines the gender of the hatchlings, with higher temperatures producing females and cooler temperatures producing males.

Most of the hatchlings do not make it to the sea because predators which include humans kill or capture them . It is estimated that only about one in a thousand leatherback hatchlings survive to adulthood. Eggs are often taken by humans from nests to be consumed for subsistence or as aphrodisiacs. The female hatchlings that do make it to the sea often return to the same nesting areas as adults to produce their own offspring. Males however never come back and spend the rest of their lives roaming the seas.

Leatherbacks are currently designated as endangered under the U.S. Endangered Species Act. The number of leatherbacks in the Atlantic appears to be stable or increasing, but the Pacific population is declining at an alarming rate due to egg harvest, fishery by catch, coastal development, and highly variable food availability. Some Pacific populations have disappeared entirely from certain areas, such as Malaysia. Scientists around the world are tracking and studying leatherbacks to learn more about these reptilian giants and how they can be saved.

Pix and facts: Internet.