Professor Tu Ming-chang of the biology department at National Taiwan Normal University explains that snakes evolved from hole-dwelling animals, and lacking limbs, they are less agile than most quadrupeds. Their vision and hearing are also poor. Hence their poison fangs are almost the only tools they have to catch food and defend themselves with.
蝮蛇科蛇類具有分泌毒素的毒腺，師大生物系教授杜銘章解釋，相較於靈活的四足動物，源自穴居動物的蛇類既乏四肢，眼力、聽力又都不佳，毒牙幾乎是獵食與禦敵的唯一工具。