Do All Mammals Have Lactose?

Lactose is the primary disaccharide in virtually all mammalian milks. It is unique among the major dietary sugars because of the β-1→4 linkage between its component monosaccharides, galactose and glucose.

Are non mammals lactose intolerant?

Most adults (around 65–70% of the world's population) are affected by lactose malabsorption . Other mammals normally lose the ability to digest lactose after weaning and this was the ancestral state of all humans before the recent evolution of lactase persistence, which extends lactose tolerance into adulthood.

Do all mammals develop lactose intolerance?

All baby mammals produce it, but it is normally switched off around the time of weaning. In people who lack this enzyme, lactose passes into the colon where it feeds bacteria that generate gas and fluid, resulting in painful bloating, cramps and diarrhoea – a condition known as lactose intolerance or malabsorption.