The Chinese zodiac animal traditionally representing the period from 1 a.m. to 3 a.m. is the Ox.
Traditional Chinese timekeeping divided the day into 12 double-hours, with each period assigned one zodiac animal. The Ox occupies the second interval, commonly called chou hour, after the Rat period from 11 p.m. to 1 a.m. and before the Tiger period from 3 a.m. to 5 a.m.
These time associations are part of the same Earthly Branch system used for zodiac years. The Ox corresponds to the branch Chou, written 丑, and the time blocks were based on local apparent time rather than modern standardized clock zones. Historical descriptions may therefore use slightly different practical interpretations.
The animal-hour tradition is distinct from the animal assigned to a person’s birth year. In traditional astrology, a birth chart can include an animal for the year, month, day, and hour, so two people born in the same zodiac year can still have different animal-hour signs.