日本北海道之所以大部分居民幾乎沒看過蟑螂，主要與其氣候、環境條件以及生活習慣有密切關聯。北海道地處日本最北端，冬季漫長且極為嚴寒，氣溫常常低於零度，甚至會長時間在零下二十度左右徘徊。這種高緯度的寒冷環境並不適合蟑螂的生存，因為蟑螂屬於喜歡溫暖潮濕的昆蟲，它們通常在氣候溫和或炎熱、濕度高的地方繁衍得最快。相比之下，北海道乾冷的冬季環境幾乎將蟑螂的生存空間徹底封鎖。

除了氣候因素，北海道的居住型態也減少蟑螂出現的可能。當地住宅多數具備嚴密的保溫與防寒設計，縫隙較少，這樣的建築特性使得害蟲難以潛入。再加上，居民在漫長冬季習慣保持室內乾燥、經常清掃，無形中也抑制蟑螂孳生的環境。

另一方面，日本南部如沖繩、九州等地，由於全年氣候潮濕溫暖，蟑螂繁殖非常旺盛，甚至會長到體型巨大，被當地人視為日常困擾。這種南北差異讓北海道居民與日本其他地區居民的生活經驗產生鮮明對比。許多北海道人甚至是到成長後，離開家鄉到東京或大阪生活時，才第一次真正看見活生生的蟑螂。這種「人生首見蟑螂」的震撼，對他們而言經常是一種難以忘懷的衝擊。

因此，北海道之所以被視為「沒有蟑螂的天堂」，並非因為完全不存在，而是因為嚴苛的自然環境與人類居住模式讓蟑螂難以繁衍，使得大部分當地居民長年都不曾與這種昆蟲正面相遇。

The reason why most residents in Hokkaidō, Japan, have never seen cockroaches is closely tied to the region’s climate, environment, and lifestyle. Hokkaidō is located at the northernmost part of Japan, with long and extremely cold winters. Temperatures often fall below freezing, sometimes even staying around minus twenty degrees Celsius for extended periods. Such a harsh, frigid environment is highly unsuitable for cockroaches, which thrive in warm and humid conditions. Unlike southern regions of Japan, Hokkaidō’s dry and cold winters create a natural barrier against their survival.

In addition to climate, the way houses are built in Hokkaidō also limits cockroach infestations. Homes there are designed with airtight insulation to retain heat and block cold air, which also reduces cracks and gaps where pests could enter. Moreover, people in Hokkaidō tend to keep their homes dry and clean throughout the long winter months, further removing conditions that cockroaches would need to live and reproduce.

In contrast, southern parts of Japan, such as Okinawa or Kyushu, are warm and humid year-round, creating ideal environments for cockroaches to grow rapidly, sometimes reaching unusually large sizes. This stark difference means that many people in Hokkaidō go through life without ever encountering cockroaches. Often, they only see one for the first time after moving to larger cities like Tokyo or Osaka, where the climate is more favorable for the insects. For them, that first encounter can be a shocking and unforgettable experience.

In short, Hokkaidō is often seen as a “cockroach-free paradise,” not because cockroaches don’t exist at all, but because the severe natural conditions and human living habits prevent them from thriving, making encounters with the insect extremely rare.