"蛇"的相關背景知識

Snake

http://en.wikipedia.org/wiki/Snake

Contents

• 1 Evolution
• 2 Digestion and diet
• 3 Skin
• 4 Perception
• 5 Internal organs
• 6 Locomotion
• 7 Reproduction
• 8 Venom
• 9 Interactions with humans
• 9.1 Snake bite
• 9.2 Snake charmers
• 9.3 Snake trapping
• 9.4 Consumption of snakes
• 9.5 Symbolism
• 10 See also
• 11 Cited references
• 12 References
• 13 External links

Forked Tongue (11/24考題相關背景知識)

http://en.wikipedia.org/wiki/Forked_tongue

A forked tongue is a tongue split into two distinct ends at the tip. This is a feature common to many species of reptiles. Reptiles smell using the tip of their tongue, and a forked tongue allows them to tell which direction a smell is coming from.

The image has given rise to the expression "to speak with a forked tongue," meaning: to say one thing and mean another or, in more general terms, to act in a duplicitous manner. Early Western films represented it as a Native American saying with the (often hostile and evil) Indians uttering phrases like, "White man speak with forked tongue".

Perception (12/1考題相關背景知識)

While snake vision is unremarkable (generally being best in arboreal species and worst in burrowing species), it is able to detect movement. Some snakes, like the Asian vine snake (genus Ahaetulla), have binocular vision. In most snakes, the lens moves back and forth within the eyeball to focus; snakes focus by moving the lens in relation to the retina. In addition to their eyes, some snakes (pit vipers, pythons, and some boas) have infrared-sensitive receptors in deep grooves between the nostril and eye, although some have labial pits on their upper lip just below the nostrils(common in pythons) which allow them to "see" the radiated heat.

A snake smells by using its forked tongue to collect airborne particles then passing them to the Jacobson's organ or the Vomeronasal organ in the mouth for examination. The fork in the tongue gives the snake a sort of directional sense of smell and taste simultaneously.^[22] The snake keeps its tongue constantly in motion, sampling particles from the air, ground, and water analyzing the chemicals found and determining the presence of prey or predators in its local environment.

The part of the body which is in direct contact with the surface of the ground is very sensitive to vibration, thus a snake is able to sense other animals approaching through detecting faint vibrations in the air and on the ground.