...And all the Dragons were sleeping in, tuckered out from a long year of not ending the world and other sorts of wackiness.
Did you know the Year of the Snake is always a yin year, meaning its nature is feminine, passive, and dark? (In comparison, a yang year is masculine, active, and light.)
The twelve animals of the Chinese zodiac are arranged into 60-year cycles, in which each animal is represented five times, one each for the five wu-xing or Chinese elements (technically, they're not elemental substances like the classical Western elements are, but are more akin to elemental phases or changes). The wu-xing cycle through the twelve animals in groups of two, one yang, the following one yin. Thus, whatever element a Snake is, the previous year's Dragon is the same element (in this case, Water), but the following year's Horse will be the next element in line (Wood).
For the Chinese, this served a practical purpose. Because directly asking a person's age was considered rude, asking, "What's your sign?", coupled with some mental arithmetic allowed ages to be safely calculated. For much of history, it was very rare for anyone to reach the age of 60, much less live past it, so this proved to be a reliable way for determining ages. Of course, it still is since a Wood Snake born in 1965 is bound to look different from one born in 1905 unless the latter has a smashing good plastic surgeon.