Milk (in a general sense) is a white fluid produced by the female in all mammals for the nutrition of their young. The ability to produce milk is one of the defining aspects of being a mammal, and milk is produced in what are called "mammary" glands. Standard milk is typically sourced from cows at "dairy farms", or farms specifically dedicated to the raising of cattle for milk production. Prior to industrialisation cows were "milked" by hand, however today there are suction pumps which perform the process.