The mystery of water bottles on Japanese streets: EXPLAINED

In Japan, it's common to see plastic water-filled bottles, known as "nekoyoke" (猫よけ) 'cat repellent', placed along streets and fences. 

These are intended to deter cats from entering certain areas or marking their territory. The belief is that light refracting through the water creates patterns that scare cats away.

However, scientific evidence supporting the effectiveness of this method is lacking. Many observe that cats often remain undeterred by these bottles. Despite this, the practice persists in various regions. ​

Interestingly, similar methods have been noted outside of Japan. For instance, in the 1980s, placing water-filled bottles to repel cats was observed in parts of Europe, though the practice eventually declined due to questions about its efficacy. ​

While the use of water-filled bottles as cat deterrents is widespread, their actual effectiveness remains questionable. Nonetheless, this practice offers insight into local customs and approaches to coexisting with urban wildlife.