00:00Imagine being the very first person to look at a wild cow and decide that its milk was
00:04exactly what you wanted for breakfast.
00:06It sounds pretty strange when you think about it, but that one weird decision actually changed
00:10the course of human history forever.
00:11So when did we actually start drinking another animal's milk?
00:14Well, it all goes back to about 9,000 years ago in a place we now call Turkey, where humans
00:19were just starting to move away from one drink, around and were beginning to live in settled
00:22farming communities.
00:23You might be wondering how can scientists possibly know what someone drank thousands
00:26of years ago.
00:27They actually find the answers in two very different places, old pieces of broken pottery
00:31and ancient human teeth.
00:32When people cooked or stored milk in clay pots, the fats from that milk got trapped inside
00:36the tiny pores of the ceramic, there they stayed for thousands of years.
00:39Researchers have analyzed these fatty residues and found direct evidence of milk use dating
00:43back to the salmon semilinium.
00:44Even more amazing is that they have found milk protein stuck in the hardened plaque on the
00:48teeth of skeletons from about 6,000 years ago, which is like a permanent record of their
00:52last meal.
00:53So if they had the milk, did they just start chugging it right away?
00:56Not exactly, because there was a huge problem.
00:58Almost every adult back then was lactose intolerant.
01:01For most of human history, we were like every other mammal and lost its ability to digest milk
01:05after we were finished being babies.
01:07If an early farmer drank a big bowl of fresh cow's milk, they would have ended up with a
01:10very upset stomach and a lot of pain.
01:12This leads to the question of how they used the milk if they couldn't drink it.
01:15The answer is actually pretty clever.
01:17They turned it into cheese and yogurt by using bacteria to process the milk.
01:20They could remove a lot of the lactose sugar, making it much easier to digest without getting
01:24sick.
01:24We have even found 7,500-year-old clay cheese strainers in Poland that look just like the
01:29colonizers we use in our kitchens today.
01:31Why would these early people go through all that trouble just for some dairy?
01:34It turns out that milk was a total superpower for survival.
01:37It provided a reliable source of calories and nutrition that didn't depend on whether your
01:41crops grew or if the hunting was good for that year.
01:43Over time, this created a huge pressure for our bodies to change so we could take full advantage
01:48of this food source.
01:49About 8,000 years ago, a genetic mutation began to spread that allowed adults to keep
01:53producing the enzyme needed to deadest milk.
01:55This is called lactase persistence, and it evolved separately in places like Europe and Africa,
01:59where people relied heavily on their animal herds.
02:01Did this new diet actually change what humans looked like?
02:04It really didn't.
02:04As studies of thousands of ancient skeletons show that in regions where people drank more
02:08milk, they actually grew taller and heavier over time.
02:10This gave them an evolutionary edge that helped them survive famines and harsh winters that
02:14might have wiped out other groups.
02:16So is everyone in the world now able to drink milk?
02:18Actually, no.
02:19Because the ability to digest milk as an adult is still the exception, not the rule for humans.
02:23Only about 35% of adults worldwide can safely consume milk today, which shows that our connection
02:28with dairy is an ongoing story of evolution that is still happening right now.
02:32Next time you grab a glass of milk, just remember that you are participating in a 9,000-year-old
02:36tradition that literally reshaped the human body.
02:40Next time you have a more chance and think what it looks like.
02:43Cheers!
02:44Thanks, everyone.
02:46This is the one of the first two months ago.
02:48Cheers!
02:48Cheers!
02:50Cheers!
02:52Cheers!
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