For the first three months of my life, I survived only on my mother's breastmilk. Quite possibly you did too.
Feeding babies on milk is so universal, it's hard to imagine what life would be like if we didn't do it. But out in the natural world, milk is common but not universal. Entire groups of animals, birds for example, don't produce anything like it and survive perfectly well.
So how and why did milk evolve? When scientists began to trace its evolutionary history, they found it is far older than we might have thought. Milk dates back hundreds of millions of years to the first animals that walked on land; although the first milk might not have been much like the stuff you put on your cereal.
Milk and breasts gained star status in the 18th century, when the Swedish biologist Carolus Linnaeus began categorizing species into groups based on their unique traits.
Some of Linnaeus's groupings have proved to be wrong, but one has held firm. He realised that a host of animals, including humans, all lactate. Females of these species nourish their young with milk from their mammary glands.
Read the full article here.