Before consumption, they are peeled. The pads of the plant (mainly used as fodder) also must be harvested by hand. The pads are cut with a knife, detaching the pad from the plant in the joint. If O. ficus-indica is cultivated for forage production, spineless cultivars are preferred, but wild plants are also used as fodder. In these cases, the spines must be removed from the pads to avoid animal damage. Primarily, this is achieved by burning the spines off the pads. Nutrients and phytochemicals O. ficus-indica for human and animal consumption is valuable for its water content in an arid environment, containing about 85% water as a water source for wildlife. The seeds contain 3–10% protein and 6–13% of fatty acids, mainly linoleic acid. However, the seeds contained in the fruits can be unpleasant to chew because of their hardness and can lead to constipation. For this reason, some agronomic studies in Italy and Mexico have focused on decreasing the seed content of Opuntia ficus-indica fruits. As the fruit contains vitamin C (containing 25–30 mg per 100 g), it was once used to mitigate scurvy. Opuntia contains selenium. The red color of the fruit and juice is due to betalains, (betanin and indicaxanthin). The plant also contains flavonoids, such as quercetin, isorhamnetin, and kaempferol. Biogeography DNA analysis indicated O. ficus-indica was domesticated from Opuntia species native to central Mexico. The Codex Mendoza, and other early sources, show Opuntia cladodes, as well as cochineal dye (which must be cultivated on Opuntia), in Aztec tribute rolls. The plant spread to many parts of the Americas in pre-Columbian times. Since Columbus, it has spread to many parts of the world, especially the Mediterranean, where it has become naturalized. References ficus-indica Cacti of Mexico North American desert flora Medicinal plants Natural history of Mesoamerica Desert fruits Energy crops Crops originating from Mexico Crops originating from the Americas Garden plants of North America Flora of Namibia Plants described in 1753 Taxa named by Carl Linnaeus Taxa named by Philip Miller