Drinking Milk

Since the time that civilization began and animal husbandry became a critical strategy for survival, drinking milk from other species, especially cow and buffalo, has become commonplace amongst many of our communities. However, are we alone in our indulgence of milking other animals to please our taste buds or empower our immunity using milk that other species produce for their progeny? Let’s find out!

History of Procuring Milk from Other Species

Let’s go back in history, about 12,000-15,000 years back, in fact. By that time, humans had learned to raise and breed small ruminants, such as goats and sheep. Man was also semi-nomadic back then, and goats and sheep didn’t post any danger to the families/tribes of humans at that time. In fact, they provided a great deal of value. Their wool could be used to weave into dresses, the skin could be made into leather items, and their bones could be used as weapons to hunt or form part of a decorative item for female members of the tribe! Moreover, the ‘operational cost’ of keeping sheep and goats in a semi-nomadic context were rather low, because these poor creatures didn’t need much farmland to graze. They could be fed any random thing and could still survive. Herding sheep or cattle was like having a refrigerator in the modern day – a storage space for future nutritional needs.

Then came along today’s favorite pet species— cats and dogs. Semi-nomadic humans of that time were familiar with the reproductive and suckling habits of 4-5 species—goat, sheep, dogs, cats etc. They learned the trick of extracting milk from these species for their own nutritional needs. Acquiring milk from these creatures also meant that they could curb their instinct of killing the animals for meat, which was a “one-time offering”, whereas extracting milk could be extended much longer, provided the animal was healthy and fertile.

Interestingly, cows as we know them didn’t exist at that time, but there was their predecessor—Aurochs—which humans tried to conquer for their ‘milking’ needs. Aurochs were bigger than typical cows and was an aggressive animal, making them difficult to tame. However, as the evolution of animals progressed, aurochs started becoming less wild and more suitable for animal husbandry, gradually evolving into the cows that we now see. Cows proved to be much better reservoirs for dairy products, due to its size and consequent milk-generating capabilities.

Are We Alone?

If you like cats and dogs, I’m sure that you have tried feeding them milk at one point or another. This milk would probably be from a cow or a buffalo. Your pet probably chugged the milk like you would down your favorite beverage! That being said, cats or dogs slurping up milk is more of an aberration than a norm. They only drink milk because they have access to it through us. In the natural environment, they don’t go out chasing cows or goats to extract their milk!

Drinking Milk Past Infancy

So, when it comes to mammals, we’re the only species to drink milk directly from other species. Or at least, we’re the only one to do so in adulthood. Although most infant/juvenile animals drink milk (from their mother), it’s because they carry an enzyme lactase to digest those milk sugars. As they grow, the gene that generates this enzyme turns off post weaning, and after that they can no longer drink that milk. In fact, humans were similarly not meant to drink milk into adulthood, but due to the evolution of our species and our habit of breeding animals for dairy products, we have adjusted to the habit of drinking milk well into adulthood. That being said, not all humans can drink milk because many are lactose intolerant. People with a lactose intolerance cannot produce the enzyme lactase, which is needed to break down milk sugars. When such people try to drink milk, they suffer from diarrhea or other nasty symptoms.

Lactase Persistence

But those who can safely drink milk are called lactase persistent. The lactase persistence, the ability to drink milk as an adult and is a trait that arose in humans as a direct result of our domestication of other dairy animals. Lactose is the main carbohydrate (also called disaccharide sugar) in animal milk. Lactase is an enzyme that breaks down the lactose carbohydrate into usable parts that is, the glucose and the galactose.

How are some people lactase persistent you may ask. Well, the genetic variants that allow (some) people to consume mammal milk safely arose about few thousand years ago as the domestic process was being undertaken. Those variations allowed humans with the gene to broaden their dietary power by incorporating more milk and dairy item to the diet. These gene variations did not happen in totality across the human race but in patches. Like for example lactase persistency is high in north India but low in the Mongolian regions.

Examples of Animal Drinking Milk of Other Species

So far, I have explained how and why we started drinking milk from cattle and how we have even convinced our pets to drink it, but what about a real wild-life example wherein an animal drinks the milk of another species. Remember, I have already ruled out mammals, but one such example is the Red Billed Oxpecker—a bird that can perch on the udders of an Impala and suck its milk. Besides the Oxpecker, birds like Seagulls and Sheathbills have been reported to pilfer milk directly from the teats of elephant seals. So, while it’s quite rare, milk stealing does happen between certain other species in the wild.