How milk composition influences mothering styles
When supporting new parents, I often discuss the fascinating comparison between humans and kangaroos. Kangaroos are among the few mammals that give birth to their babies at a less developed stage than humans. After birth, kangaroo joeys crawl up into their mother's pouch and attach themselves to the nipple, essentially feeding around the clock. Similarly, human babies, if given the chance, instinctively crawl up their mother's chest and latch onto the breast for nourishment. They require frequent feeding. Unfortunately, unlike kangaroos, we don't have a natural pouch. However, we have the advantage of strong arms, a comfortable curvy body to lie on, and the ability to create a makeshift pouch by wrapping fabric around ourselves.
Humans belong to the category of "carry" mammals, which includes apes and marsupials. These mammals give birth to the most underdeveloped infants compared to other mammals. Our babies are entirely reliant on their mothers for sustenance, warmth, and protection. They need to be fed frequently, resulting in human breast milk having relatively low levels of fat and protein.
In contrast, there are other types of mammals known as "follow" mammals, such as horses and giraffes. Their offspring can walk shortly after birth and can keep up with their mothers, enabling them to feed more intermittently. The milk of these mammals has slightly higher fat and protein content than that of carry mammals. "Nest" mammals, like dogs and cats, leave their babies for periods of time and return intermittently to nurse them. Consequently, their milk needs to be higher in fat and protein to sustain the babies during the waiting periods. Lastly, "cache" animals, including rabbits and deer, leave their babies in a safe location and return every 12 hours or so to nurse them. As a result, their milk contains much higher levels of fat and protein to provide sustenance for longer durations.
Many baby books mistakenly categorize humans as nest animals, when in fact, we are carry mammals. Human babies naturally seek constant physical contact and frequent feeding. Our breast milk is perfectly designed to meet these needs. This behavior is entirely normal for newborns.