The animals belonged to smallholder and landless farmers who used them for draught purposes for preparation of rice paddies or sugar-cane harvesting.
A vast number of lowland rice paddies were created in the sixteenth and seventeenth centuries.
The eldest man of a household oversees the planting, harvesting and marketing of rice from his household's paddies.
These dischargers shut automatically with the rising of the tide, keeping salt water out of paddies.