Legless lizard or a snake?
Senin, 02 Desember 2013
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Lizards and snakes are reptiles. During this time, the both reptiles can be distinguished, although they have the same scaly body. Snake is easily recognizable because it has no legs. While lizards generally have four legs to move. But is it true that all the lizards have legs?
Apparently there are several species of lizards which do not have legs and called it as the legless lizard. One of these are the glass lizard. Legless lizards evolved from legged lizard, familiar types of lizard encountered. Instead, it snakes evolved from four-legged ancient serpent, the type of snake that most of us have never seen it.
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| The Bakersfield legless lizard (Anniella grinnelli), which today ranges from downtown Bakersfield in the southern San Joaquin Valley to the Carrizo Plain National Monument 30 miles to the west. (Picture from: http://www.livescience.com/) |
Legless lizard fossil was almost as old as the ancient snake fossils that still has the front legs. Based on the fossil evidence, the scientists concluded that the snakes and legless lizards lost their legs in the range of nearly the same time.
Legless lizard and a snake does look very similar. Both have elongated cylindrical body, a forked tongue, padded leather scales, and crawling with winding movement pattern like the letter "S". They are equally spread across the continents, except at Antarctica, and can thrive in all kinds of climates: cold, hot, wet, and dry.
So, how do we know which snakes and legless lizards? Legless lizards are always looking for small prey. Therefore, lizards do not have flexible jaws. Lizards can not disconnect the lower jaw and upper jaw to swallow prey larger than the size of their head. Instead, the snake can do. Adult pythons for example, is able to swallow a goat or a pig.
Other differences are more easily observed is the legless lizards have eyelids. That is, the lizard could blink. Unlike the snake. All kinds of snakes do not have eyelids alias is always awake. In exchange, a transparent snake eyes protected scales.
The other characteristics of the legless lizard is having ear holes. This means that the lizards can hear the sound. While snakes do not have it. Auditory snakes are not well developed, but is able to detect prey or threats through vibrations in the ground.
Legless lizards can detach their tails when threatened by predators. It is one of self-defense mechanism. When the predator is busy with their tail, the lizard can escape. Able to regenerate its tail lizard though sometimes takes several months. Removing the tail ability is not owned by snakes.
Most of the legless lizard has a long tail. At least two-thirds of the total body length is a legless lizard tail. Unlike the snake, the body is always longer than the tail.
Here are the difference between Legless Lizards and Snakes,
Eyelids
Legless lizards have movable eyelids, whereas snakes do not possess eyelids at all.
Jaws
The jaws of legless lizards are not flexible, and they are unable to open their jaws wide like snakes. Hence, they tend to eat smaller prey like beetles, snails, grasshoppers, and spiders, which are generally smaller than their own heads.
Ears
All species of legless lizards have external ear openings, whereas, ears are absent in snakes.
Locomotion
A legless lizard uses its sides to move, which limits its movement from side to side, as opposed to the snake, which can use both its belly scales as well as sides for motion. Thus, a snake has a greater range of movement. A legless lizard, due to its inability to expand and contract its belly scales, is unable to move on flat surfaces, like paved roads.
Tail
The long tail of a legless lizard makes up almost two-thirds of its entire body length, whereas, the body proportion of a snake is the exact opposite. A snake has a long body, and a shorter tail in comparison.
The tail is the most prized possession of a legless lizard, and if threatened, it will cut off the tail and run away. This is an effective mechanism to distract predators and save its life. The tail often breaks in more than one piece, which may appear like shattering of glass, which is why, these lizards get the name glass lizards. However, only one additional tail can be regenerated by the glass lizard in its lifetime. The regeneration process may take several months or even a year or two, and the regenerated tail is often shorter and paler in appearance. *** [EKA | FROM VARIOUS SOURCES | LIVESCIENCE | MAHARDIKA SATRIA HADI | KORAN TEMPO 4418]
Here are the difference between Legless Lizards and Snakes,
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| Difference between Legless Lizards and Snakes. (Picture from: http://www.buzzle.com/) |
Legless lizards have movable eyelids, whereas snakes do not possess eyelids at all.
Jaws
The jaws of legless lizards are not flexible, and they are unable to open their jaws wide like snakes. Hence, they tend to eat smaller prey like beetles, snails, grasshoppers, and spiders, which are generally smaller than their own heads.
Ears
All species of legless lizards have external ear openings, whereas, ears are absent in snakes.
Locomotion
A legless lizard uses its sides to move, which limits its movement from side to side, as opposed to the snake, which can use both its belly scales as well as sides for motion. Thus, a snake has a greater range of movement. A legless lizard, due to its inability to expand and contract its belly scales, is unable to move on flat surfaces, like paved roads.
Tail
The long tail of a legless lizard makes up almost two-thirds of its entire body length, whereas, the body proportion of a snake is the exact opposite. A snake has a long body, and a shorter tail in comparison.
The tail is the most prized possession of a legless lizard, and if threatened, it will cut off the tail and run away. This is an effective mechanism to distract predators and save its life. The tail often breaks in more than one piece, which may appear like shattering of glass, which is why, these lizards get the name glass lizards. However, only one additional tail can be regenerated by the glass lizard in its lifetime. The regeneration process may take several months or even a year or two, and the regenerated tail is often shorter and paler in appearance. *** [EKA | FROM VARIOUS SOURCES | LIVESCIENCE | MAHARDIKA SATRIA HADI | KORAN TEMPO 4418]
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Judul: Legless lizard or a snake?
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