My Science School

               Our Earth is a sanctuary of biodiversity and there are creatures with the strangest characteristics. One such animal is the tuatara.

               The tuatara is a strange reptile. It looks like a lizard; however, it is not a lizard. It is not a snake or turtle or crocodilian either. These creatures have remained beyond evolution as well. Tuataras have remained unchanged over millions of years. The tuataras in the age of the dinosaurs were the same as the tuataras of today. The tuatara is slow by nature. They grow slowly. Male tuataras grow to a length of 60 centimetres, but females are slightly shorter. The female tuatara lays 10 to 10 eggs in a shallow burrow. The eggs take long 15 months to hatch. This is the longest time for any reptile. Tuataras can live for over 120 years.

               Although snakes frighten us in several ways, it generally does not do so by flying! Snakes do not usually fly, because they do not have wings. However, if you ever go to Southeast Asia, you might see a snake flying over your head! If snakes do not have wings, how do they manage to fly?

               These snakes, in fact, are not really flying like a bird. They are merely gliding from one tree to another. A flying snake launches itself at high speed from a perch on a tree, raises its limbs, and flattens its body to form a kind of parachute. A flying snake cannot take an upward flight. They glide only downwards. It may even swish and contort itself in flight so that it can control where it lands.

               Flying snakes can hunt their prey in the air too, crushing small animals with their powerful jaws. A flying snake can glide as much as 24 metres in the air!

               There is a group of is islands 965 kilometres off the coast of Ecuador in South America. They were discovered in 1535, and are called Galapagos Islands. The islands were famous for the huge tortoises that lived there. The name of the islands derives from these reptiles. ‘Galapago’ in Spanish means saddle, and refer to the tortoise shell. It is believed that long, long ago these giant turtles must have arrived in the island from South America, on pieces of driftwood.

               Galapagos tortoises are the largest tortoises in the world. One of the most amazing facts about the Galapagos Giant Tortoise is that they keep growing for 30 to 40 years, reaching almost 1.5 metres. They also weigh about 227 kilogrammes. They are also the longest living of all vertebrates – that is, animals with backbones. Do you know these animals outlive humans? The oldest on record lived for 152 years!

               Throughout the 19th century, giant tortoises were valued by sailors as food supply. Thousands of these tortoises were killed and the species died out. The last surviving tortoise called Lone-some George died in 2012 at the Galapagos national park in Ecuador.

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            Some reptiles are excellent hunters. Crocodiles and alligators, in particular, are very clever at stalking, capturing and killing their prey. The gharial crocodile, which has a long narrow snout, eats mostly fish, and it captures its prey by a rapid sideways snap of its tooth-lined jaw. Alligators and crocodiles with broader snouts also eat fish, but their diets vary according to  their age.

            The young reptiles feed mainly on insects, spiders, crabs and small frogs. They will circle their prey with their bodies and with a sudden sideways movement of their jaws, trap them and eat them.

            Adult crocodiles and alligators eat small mammals, birds, turtles and other reptiles. They will approach their prey stealthily with their bodies submerged under water and only their eyes and tip of their snout above the water. When they are near the prey, they submerge themselves completely. With the help of their powerful tails, they reach up to the prey and capture them. Their vice-like, tooth-lined jaws snap shut with an enormous force and kills the smaller prey immediately. Larger animals are dragged underwater, drowned and then killed and eaten, sometimes over the span of several days.

Picture credit: google

               We all have seen dragons in movies. These huge and fearsome animals can fly and spit fire. Have such animals ever existed in the past? Scientists say that, if we forget the fire-spitting part, these animals resembled a flying reptile that lived a long time ago!

               The Archaeopteryx was a part reptile and part bird that lived 150 million years ago. This animal is a wonderful example of an in-between creature, which is neither a bird nor a reptile fully. Several fossils of this reptile-bird have been found in fine-grained stone. The skeleton look like that of a dinosaur but it shows the presence of feathers. Feathers are the most important feature of birds and they have evolved from the scales of reptiles. The archaeopteryx had a toothed jaw, a long tail and a weak breastbone. Unlike the bones of birds, all the bones of birds, all the bones of the archaeopteryx were solid.

               Do you know there is an uncanny connection between the cuckoo and the crocodile? The feathers of the archaeopteryx tell us that the crocodile, in fact, is related to the cuckoo.

What do we know about the archaeopteryx?

               The first bird to inhabit the Earth is believed to be the archaeopteryx (meaning ‘ancient wing’). It was a cat-sized bird, with several reptilian features. It had a beak containing sharp teeth, claws on its wings, and a long tail with bones in the middle. They had wings, feathers and a furcula. The furcula, or wish bone in birds, is a forked bone that joins the right and left shoulder joints. Not much is known about this bird’s direct ancestors or descendants.

                We are all scared of snakes. Have you ever wondered how these animals move about without legs? Snakes have descended from lizards. In fact, they evolved from lizards millions of years ago. Scientists are still not certain regarding the group of lizards from which snakes evolved. We depend on fossils to study evolution and sometimes a snake does not make a good fossil. They leave only pieces of backbone and the odd skull in poor conditions.

                The most primitive living snakes lived underground by digging holes in the earth. Therefore, some scientists believe that snakes come from burrowing lizards, which had much reduced limbs. Others, on the other hand, think that snakes evolved in the sea.

                Many scientists hold the view that lizards descend from a super family of non-burrowing lizards known as platynota. The Gila monster, beaded lizard and a poisonous lizard called Lanthanotus belong to this super family. Members of this family do have some features in common with the snakes. The backbone and the tongue of these lizards and the snakes are similar in shape. The two halves of the lower jaw are not firmly joined.

                Therefore, lizards belonging to the super family platynota are regarded as the ‘great grandfathers’ of snakes.

Picture credit: google