上古之時，先民因生活需要而關心氣候變化，並經由反覆觀察、累積經驗，多能熟知天文星象與氣候變易之關聯，此乃經驗累積為生活常識，並編為諺語、記為文字以傳承後人。《詩經．小雅．漸漸之石》記載先秦時代即以「有豕白蹢，烝涉波矣」為天將降雨之徵兆，本文搜羅文史典籍中與「豕」相關之神話傳說，並結合出土文物、當代農牧知識等資料，分別探究「豕烝涉波」與「有豕白蹢」說法之根源，認為先民觀察「豕」之生活型態，發現降雨前天氣悶熱，此時豬群多聚集於泥水坑或河川泡水散熱，先民每見豬群涉入溝瀆河川後便降大雨，因而歸納此現象為降雨之兆，並由此附會出雨神、水神、豬龍等與降雨、大水、湧泉相關的神話傳說，亦將烏雲籠罩銀河想像為是群豬渡河之狀。由此可以看出先秦時代的百姓於觀察天象、預測氣候已有相當豐富之經驗，亦可追溯出遠古社會重視水源，而將「豕」與雨、水做出強烈意象聯想之早期根源，並梳理出自上古至今世相關傳說衍生發展之脈絡。

In the archaic periods the ancients concerned about climate changes out of necessity. From time to time they observed the weather and accumulated certain knowledges, therefore, were acquainted with correlations between astronomical phenomena and weather fluctuations. Their day to day experiences turned into knowledge, compiled into proverbs and preserved in writing for posterity. According to “The Book of Songs, The Minor Odes, The Towering Rocks” in pre-Chin dynasties: “Swines with white hooves wading through streams when rain falls are imminent.” Drawing heavily on literary and historical writings on swines combined with artifacts uncovered and agricultural and pastoral expertises at the time. This study traces the origins of two proverbs: “swines wading through streams” and “swines with white hooves.” The ancients closely observed the lifestyles of swines and noticed that when temperature rises before rain falls swines flock and soak in muddy water holes or rivers to disperse the heat away. They saw rainfalls when swines wade into ditches and regarded such phenomena as signs of rain. Consequently, evolving the rain god, water god and swine dragon legends and mythologies associated with rain, flood, gushing of water and envisaging overcasting sky as swines crossing rivers. It is suggested that commoners in as early as pre-Chin dynasties were very knowledgeable about astronomical phenomena and weather forecast. It can be derived from the studies that archaic societies regarded water as valuable sources, thus conjured images highly associated with swines, rain and water. Therefore we can unwind the thread of the ongoing stories and legends from ancient times to the present day.