There is an “Eto（干支）” culture in Japan. It is a concept imported from ancient China as it is called Chinese Zodiac in English.
There are 12 kinds of animals allocated every year, and they change in order. This year’s animals are dogs, 2017 was rooster and 2016 was monkey.
Of course, animals have no meaning, but the animal-related goods can be sold as a symbol of the year. In shorts it is one of commercial customs.