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| Sunday, 30 January 2005 |
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Junior Observer |  |
| News Business Features Editorial
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Frogs, reptiles and lizards : The bizzare and amazing Amphibians and reptiles are both vertebrates but they are two separate groups of animals. While amphibians include the frogs, toads, salamanders, newts, as well as a limbless group known as caecilians, the reptiles include the snakes, lizards, crocodiles, turtles and the lizard-like tuatara. Amphibians have soft, moist skins and obtain their body heat from the environment. The life cycle of most amphibians include three stages: an egg, a free-swimming larval or tadpole stage, and the air-breathing adult. Reptiles have dry, scaly skin. Most reptiles lay eggs but they differ in structure from the eggs of amphibians. The evolution of amphibians over about 300 million years has given rise to more than 3000 highly successful species. Many amphibians are brightly coloured. Some produce poisons from skin glands, while some have complex vocalisations and remarkable forms of reproduction. The few groups of reptiles who have survived the great age of the dinosaurs, which numbers over 6,000 species, are highly specialised in their defence, feeding and reproduction. Many new species of amphibians and reptiles are being discovered all the time. At the same time many existing species are endangered, and some have even become extinct. We still know very little of these groups of animals which are very fascinating. Let's look at a few unusual lizards, reptiles and frogs today. **** Golden Arrow - Poison Frog
Secretions from the skin of this frog have for centuries been used by South American Indians as a deadly and effective poison which, when used on arrow tips, can kill large prey in just seconds. The poison from one frog is sufficient for use on up to 40 arrows. However the little frogs have to be killed to obtain this poison. Not much study has been done on this beautifully coloured frog that eats small insects and other tiny invertebrates. It has a lifespan of 2-3 years. The female produces six eggs which are then cared for by the male, who later carries the tadpoles on his back to a place of safety. **** Tuatara - world's most amazing reptile
What is most amazing about this reptile which has a strong skull, strangely shaped ribs and a primitive backbone when compared to other reptiles, is its 'third eye' or pineal eye. Externally this eye appears as a tiny spot on top of the animal's head, but there is an internal eye. The retina is situated on top of the animal's brain, just below a small hole in its skull. What purpose it serves or why it is there, no one really knows yet.An adult tuatara male is about 60 cm (2 ft) but the female is smaller. It eats almost anything it can find, but prefers insects and spiders.The tuatara does not breed until it reaches the age of about 20 years. Fully grown males may be about 60 years old. Some may live for 100 years. The female lays about 10 eggs in a shallow scoop, covers it with dirt and gets on with her life. The eggs may take as long as 15 months to hatch, the longest incubation period for any reptile. The tuatara which is classed in a special group of its own is a slow moving creature and has a body temperature of 20-25 degrees Celsius, which is the lowest for any reptile. **** Thorny Devil - the bizzare lizard
The Thorny Devil is a small lizard reaching a maximum length of about 15 cm (6 inches). The female lays about eight eggs in a specially prepared tunnel. Compared with the small size of the mother lizard, the newly hatched young are rather large, measuring about 6 cm (2.2 inches) in length. Ants are its favourite food. It is known to sit for hours by a nest, flicking up one ant at a time. Thousands of ants may go into one meal. It can eat about 45 ants in a minute When it comes to drinking water, the thorny devil has a most unusual way of doing it. It drinks from its body. On the surface of the animal's skin are thousands of tiny grooves which allow water to spread and move very quickly over its body, as if it were made of blotting paper. Then when the deserts become very cold at night, dew forms on the lizard's skin. The tiny droplets spread through the body and reaches the lips of the lizard, which then sips the water. Many predators avoid spiny-looking prey and in this respect the Thorny Devil has a unique protection from its enemies. **** Tree Frog - amphibian acrobats
The Common European Tree Frog is a medium-sized frog which is about 5 cm (2 inches) with very long limbs in comparison to its body. Considered the acrobatic clowns of the amphibian world, tree frogs are extremely agile and can cling to the most delicate of things. It can walk along narrow branches and leap among stems. The disc-like adhesive pads enable, it to cling to branches. Active mainly at night, the tree frog eats night-flying insects and other invertebrates. The life span is six years. The Little Cricket Frog, which is a North American tree frog can jump up to 35 times its own length of 3 cm (1.2 inches) and can also leap at the same speed as a person walking. |
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A small, highly coloured frog which lives only in Central and South
America, the Golden Arrow-Poison Frog is considered the most deadly of all
amphibians.
If you ever see a Tuatara you might think it is a lizard but in reality
it is a reptile. In fact, it is the world's most amazing reptile which is
found in a few isolated islands off New Zealand. It lives mostly in
burrows. It is the sole survivor of what was once a widespread and
abundant group of reptiles which existed during the age of dinosaurs.
Found in many desert regions of Australia, this bizarre lizard is
easily identified by the many large spines which entirely cover its body
and tail. Even though it has a weird appearance and a name, it is
completely harmless. It is also a slow moving creature like the tuatara,
and when frightened it tucks its head between its front legs.
About 500 species of tree frogs are found throughout the world except
in Antarctica. These tree frogs vary in size.
