Protein-rich diet and water balance as limiting factors in the geographical distribution of the Norway rat, Rattus norvegicus

The geographical distribution of the Norway rat, Rattus norvegicus, is constrained by protein-rich diets and water balance, as demonstrated through surveys across subarctic to tropical zones. In Hokkaido's uninhabited islands (Yururi-Moyururi), rats adapted to snow cover and seasonal recruitment, while in Yokohama, population fluctuations were observed. On Tokyo Bay's Kaiho-2 islet, dehydration halted recruitment during winter, leading to body mass loss due to fat consumption. Similarly, in the Ogasawara Archipelago's Hahajima Islands, chronic dehydration forced rats to rely on plant matter and lose weight. In contrast, urban environments like Bangkok and Chanthaburi, Thailand, supported rat populations by providing water system food sources. These findings highlight protein availability and hydration as critical factors shaping the rat's global distribution.

Yabe, T. (2018). Protein-rich diet and water balance as limiting factors in the geographical distribution of the Norway rat, Rattus norvegicus Medical Entomology and Zoology, 69(2), 41–47. https://doi.org/10.7601/mez.69.41