When Was the Worst Time to Be Born as an Ancient Human?

[00:00:00]Picture this.

[00:00:01]You are born.

[00:00:03]Congratulations. You have successfully completed the first step of existing, which in the context of this video is a more significant achievement than it sounds, because the when and where of your birth is going to determine almost everything about whether the next few years of your life are survivable, challenging, or a specific category of catastrophic that we are going to spend the next several minutes examining in careful, slightly uncomfortable detail.

[00:00:29]You have no say in any of this. You did not choose your birth year, your birth latitude, your birth climate, or the specific geological and ecological circumstances of the landscape your mother was standing in when your arrival became inevitable. You arrived when you arrived, where you arrived, into whatever conditions the ancient world happened to be producing at that precise moment. And depending on when that moment was, the difficulty setting of your existence just got adjusted somewhere between moderately hard and something that does not have a diplomatic description.

[00:01:01]Because here's the thing about being born as an ancient human that the popular imagination consistently underestimates, the baseline was already brutal.

[00:01:11]Before you add any specific catastrophic variables, before you factor in volcanic winters, mega droughts, glacial advances, or the particular combination of ecological collapse that we are going to work through in this video, the standard operating conditions of ancient human life were challenging in ways that make most historical complaints about difficult circumstances look like minor scheduling inconveniences.

[00:01:35]Ancient infant mortality was staggering by modern standards. Ancient childhood was a sustained negotiation with malnutrition, parasitic load, injury, and the full predator roster of whatever continent you happened to be born on.

[00:01:49]Ancient adulthood was physically demanding in ways that left skeletal marks that paleoanthropologists can read like a biography of hard use, that is the baseline, that is the normal. And then there were the periods that were worse than normal, sometimes dramatically, sometimes catastrophically, sometimes in ways that pushed the human species to the edge of what surviving means at the population level. Identifying those periods, examining what specifically made them so dangerous, and understanding what it would have meant to be born into them as a small, helpless, ancient infant with no knowledge of what was coming is what this video is about.

[00:02:26]And the answer involves a supervolcano, a protracted ice age advance, a mega drought that reshaped an entire continent, and at least one period where the total human population may have dropped to numbers so low that the species' continued existence became a genuinely open question.

[00:02:46]Start with what might be the single worst moment in the entire history of human existence to draw your first breath.

[00:02:53]The period around 74,000 years ago, during and immediately after the Toba supervolcanic eruption.

[00:03:00]Toba was not a volcano in the sense most people picture when they hear the word.

[00:03:04]It was not a dramatic cone erupting dramatically into a dramatic sky in a way that is visually striking and locally devastating.

[00:03:12]It was a caldera system, a massive magmatic reservoir beneath what is now Lake Toba in Sumatra, Indonesia, that had been building pressure across an interval of geological time, and that approximately 74,000 years ago released that pressure in an eruption so large that the scale is difficult to communicate without comparison.

[00:03:33]The Toba eruption ejected an estimated 2,800 cubic kilometers of material into the atmosphere.

[00:03:40]For reference, the 1980 Mount St. Helens eruption ejected approximately 1 cubic kilometer of material.

[00:03:46]Krakatoa, in 1883, ejected approximately 25 cubic kilometers. Toba ejected more than 100 times the volume of Krakatoa and produced ash fall deposits that are identifiable across South Asia, the Arabian Peninsula, and parts of Africa.

[00:04:05]A geographic distribution of eruption debris that reflects an atmospheric injection of material so massive that it altered global climate for years after the eruption itself.

[00:04:16]The immediate consequences of the Toba eruption for ancient humans living in its vicinity were total. Population centers in South and Southeast Asia would have been directly destroyed by ash fall, pyroclastic flows, and the cascading ecological collapse that followed the destruction of vegetation across affected regions.

[00:04:34]But the longer-term global consequences were what made Toba catastrophic for ancient humans far beyond the eruption zone, and what made being born in the years immediately following it one of the worst timing decisions any ancient human infant could have made.

[00:04:50]The atmospheric injection of sulfur dioxide from the eruption created a sulfate aerosol layer in the stratosphere that reflected incoming solar radiation back into space, reducing the amount of solar energy reaching the Earth's surface and producing a volcanic winter that lasted years.

[00:05:08]Possibly a decade or more in its most severe phases.

[00:05:13]Average global temperatures dropped substantially during this period.

[00:05:17]The effects on plant productivity were immediate and severe. Reduced sunlight meant reduced photosynthesis.

[00:05:23]Reduced photosynthesis meant reduced plant growth.

[00:05:27]Reduced plant growth meant reduced herbivore populations.

[00:05:31]Reduced herbivore populations meant reduced prey availability for every carnivore and omnivore in the food web.

[00:05:39]Including the ancient humans trying to survive across the now darkened and cooling landscapes of Africa, Asia, and Europe.

[00:05:48]For ancient infants born during the Toba volcanic winter, the environment they arrived into was one in which the food web supporting their caregivers survival had been substantially compromised.

[00:05:59]Ancient mothers under severe nutritional stress produce less milk and milk of reduced nutritional quality.

[00:06:06]Ancient groups under severe resource pressure face the impossible calculus of allocating insufficient food across multiple individuals with competing needs.

[00:06:16]The social and practical support structures that made ancient infant survival possible, the alloparenting networks, the food sharing, the distributed care of the group, become strained when the group itself is struggling to meet basic caloric requirements.

[00:06:34]The genetic evidence that something catastrophic happened to human populations around this time period is striking.

[00:06:42]Studies of human genetic diversity consistently find evidence of a severe population bottleneck, a dramatic reduction in the human breeding population that occurred approximately 70 to 80,000 years ago.

[00:06:56]The specific timing and its alignment with the Toba eruption is debated among researchers, with some arguing for a direct causal relationship and others proposing that the bottleneck reflects other factors or that human populations were more resilient than the volcanic winter hypothesis implies.

[00:07:14]What is not debated is that the genetic diversity present in all living humans today reflects descent from an ancestral population that was, at some point in this general time frame, dramatically smaller than the populations that preceded it.

[00:07:29]Some estimates have placed the human breeding population during the bottleneck period at a few thousand individuals, possibly fewer.

[00:07:37]Being born as an ancient infant into a species population of a few thousand individuals scattered across a cooling ash-darkened landscape with compromised food availability and destabilized ecological systems.

[00:07:52]While the volcanic winter produced by the largest eruption in recent geological history slowly worked its way through the global climate system.

[00:08:01]This is a strong candidate for the worst timing in the history of human birth.

[00:08:06]Move forward in time from Toba to examine a different category of catastrophic birth timing.

[00:08:13]The periods of most severe glacial advance during the last glacial maximum, approximately 20 to 25,000 years ago.

[00:08:22]This is a different kind of bad from Toba.

[00:08:25]Not a sudden catastrophic event, but a sustained progressive environmental deterioration that made survival progressively more demanding across generations.

[00:08:36]At the peak of the last glacial maximum, ice sheets covered enormous portions of the northern hemisphere.

[00:08:42]Northern Europe under kilometers of ice.

[00:08:45]Much of North America buried under the Laurentide ice sheet. Sea levels approximately 120 m lower than today exposing continental shelves and creating land bridges, but also dramatically reducing the total area of productive coastal and lowland habitat available to ancient populations.

[00:09:04]The areas that remained ice-free were largely cold, dry, and swept by katabatic winds draining off the ice sheet margins.

[00:09:13]Conditions that supported the mammoth steppe ecosystem, but that were demanding for the humans living in it in ways that winter severity alone does not fully convey.

[00:09:23]Ancient infants born during the coldest phases of the glacial maximum were born into conditions where the energy cost of thermoregulation was highest, where the caloric demands on their caregivers were most extreme, and where the failure of any element of the survival system, adequate clothing, functional shelter, sufficient fuel supply, maintained fire, could cascade rapidly into life-threatening cold exposure.

[00:09:48]The failure modes in this environment were fast and unforgiving. An infant is the most thermally vulnerable member of any group. High surface area to volume ratio. Limited ability to generate metabolic heat through shivering.

[00:10:02]Complete dependence on external warmth from caregivers and fire. By the way, if you want to go even deeper into the secret lives of ancient humans, I just launched a full course called The Secret Lives of Ancient Humans. 10 modules, 3-plus hours of content covering everything we never talk about on YouTube. What they feared, how they communicated, what hunted them, and much more. Plus an exclusive PDF guide included. Link in the description.

[00:10:32]See you inside.

[00:10:33]In an environment where maintaining adequate warmth was a sustained technical and logistical challenge for the entire group, the infant was the member for whom the margin between adequate and insufficient was smallest.

[00:10:46]The caloric mathematics of the glacial maximum were also brutal for ancient infants in a specific and direct way.

[00:10:53]Breastfeeding is calorically expensive.

[00:10:55]Producing adequate milk requires the mother to consume significantly more calories than her own maintenance metabolism requires.

[00:11:04]In an environment where caloric acquisition was demanding and where food availability fluctuated seasonally in ways that could produce significant deficits during winter months, the competition between a mother's own caloric maintenance and the caloric cost of adequate milk production was a real and recurring constraint.

[00:11:25]Ancient infants born in the worst months of the worst years of the glacial maximum were born into a caloric system under maximum stress with the least margin for the shortfalls that harsh winters reliably produced.

[00:11:39]Now shift to a different geographic and temporal context that produced its own specific category of catastrophic birth conditions.

[00:11:47]The African Humid Period and its termination.

[00:11:52]The African Humid Period, sometimes called the Green Sahara, was a phase roughly 11,000 to 5,000 years ago during which the Sahara Desert, now one of the most extreme environments on Earth, was a productive landscape of lakes, rivers, grasslands, and woodland.

[00:12:09]The shift from the glacial maximum to the warmer, wetter conditions of the early Holocene transformed the Sahara in ways that allowed human populations to expand into areas that had previously been uninhabitable desert, producing archaeological evidence of human occupation across regions now completely devoid of significant human presence.

[00:12:30]The termination of the African Humid Period, the transition back to arid conditions that produced the modern Sahara, happened across a period of perhaps a few centuries in some regions, though the timing and pace varied across the enormous geographic extent of the Saharan zone.

[00:12:47]For ancient communities that had established themselves in the interior of the Green Sahara during the productive period, communities built around the lakes and rivers that supported their subsistence, the contraction of these water resources and the advancing desertification of the surrounding landscape created a slow-motion crisis of habitat loss that accelerated as the arid conditions intensified.

[00:13:10]Ancient infants born into communities in the Saharan interior during the late phases of this transition arrived into groups that were losing the resource base that had supported them, that were facing the difficult decision of when and where to relocate, and that were experiencing the social stress of a community confronting existential displacement.

[00:13:31]The options for these communities were coastal zones, the Nile Valley, and other refugia where water and productivity remained.

[00:13:41]All of which required displacement from the landscapes their communities had occupied with the social disruption and resource competition that displacement entails.

[00:13:50]Being born into a community in the process of losing its homeland to advancing desert with the associated food and water stress, the social disruption of forced migration, and the resource competition encountered at the destination.

[00:14:04]This is a specific and under-appreciated category of catastrophic birth timing that affected populations across a vast region across the centuries of the Saharan desertification process.

[00:14:15]The Younger Dryas cold event, a sudden return to near glacial conditions that occurred approximately 12,900 years ago and lasted approximately 1,200 years, represents another period that elevated the difficulty of ancient infant birth dramatically in specific geographic contexts.

[00:14:34]The Younger Dryas interruption of the warming trend that had been underway since the glacial maximum was rapid by geological standards.

[00:14:41]Temperature drops of 10° C or more occurred over periods that in the geological record appeared nearly instantaneous.

[00:14:49]The ecological consequences were severe.

[00:14:51]Plant communities that had expanded northward and up slope during the preceding warming rapidly contracted or collapsed.

[00:14:58]Animal populations that had shifted their ranges in response to warming were exposed to conditions outside the range they had adapted to.

[00:15:06]For ancient human communities in Europe and Western Asia that had been adjusting their subsistence practices to the changing conditions of the late glacial warming period, the sudden return of near glacial conditions during the Younger Dryas was a disruption for which their adjusted strategies were not prepared.

[00:15:22]The prey populations they had begun targeting, the plant foods they had begun incorporating as conditions warmed, the seasonal patterns of resource availability they had calibrated their annual movement cycles to.

[00:15:35]All of these were destabilized by the sudden climatic reversal.

[00:15:39]Ancient infants born in the early centuries of the Younger Dryas were born into communities that were scrambling to adapt strategies calibrated for warming conditions to a sudden return of cold, with the lag time between the environmental shift and the behavioral and technological adaptations required to address it, representing a period of elevated vulnerability.

[00:16:02]The communities that navigated this transition successfully were those with the adaptive flexibility and knowledge base to shift strategies rapidly.

[00:16:11]The infants born during the transition period, before those adaptations were consolidated, faced the highest risk from the mismatch between community capability and environmental demand.

[00:16:22]The specific experience of being an ancient infant during any of these catastrophic periods shares certain features that are worth examining directly because they translate the abstract population level catastrophe into the specific lived experience of an individual tiny person who had no understanding of what was happening and no capacity to do anything about it.

[00:16:46]Ancient infants during catastrophic periods were born into groups that were stressed in ways that affected everything about the infant's immediate environment.

[00:16:54]Stressed caregivers have elevated cortisol levels, the primary stress hormone, and infants in close physical contact with stressed caregivers are exposed to physiological stress signals through the shared sensory environment of carrying and nursing.

[00:17:09]Elevated cortisol in breastfeeding mothers is transferred to infants through milk.

[00:17:14]The physical and hormonal stress environment of a group under catastrophic resource pressure was not invisible to the infants within it.

[00:17:22]It was experienced as a set of physiological signals that the developing infant nervous system responded to in ways that shaped its development.

[00:17:30]The nutritional quality of early infant feeding during catastrophic periods was directly affected by maternal nutritional status.

[00:17:37]Severe maternal malnutrition reduces both milk volume and the nutritional density of breast milk with specific micronutrient deficiencies in the milk corresponding to deficiencies in the mother's diet.

[00:17:49]An ancient infant born during a volcanic winter or a severe drought into a malnourished mother's care received sub-optimal nutrition at exactly the developmental period when nutritional adequacy has the most consequential effects on brain development, immune system development, and the physical growth that determines the infant's capacity to survive childhood.

[00:18:09]The alloparenting networks that were critical to ancient infant survival under normal conditions were strained during catastrophic periods in ways that reduced their effectiveness exactly when it was most needed.

[00:18:20]When entire groups were nutritionally stressed and physically depleted, the older women who provided crucial supplementary care to infants while mothers forged were less capable of sustained caregiving.

[00:18:31]The older children who might carry or entertain younger siblings in normal times were themselves more vulnerable and more demanding of adult attention during catastrophic periods.

[00:18:42]The social infrastructure of infant care, which was robust and effective under baseline ancient conditions, became less reliable precisely when the infants who needed it were born into conditions that made them most vulnerable.

[00:18:56]The question of how ancient communities made decisions about infant survival during periods of catastrophic resource pressure is one that is documented in various ways across the anthropological record and that represents one of the more difficult dimensions of ancient life to examine honestly.

[00:19:12]The archaeological record contains evidence of differential investment in infant survival that reflects the resource constraints facing communities.

[00:19:21]Evidence of practices that are difficult to discuss without the clinical distance of demographic necessity.

[00:19:27]Ancient communities under severe resource pressure faced decisions about which members to prioritize that modern societies, with their surplus resources and their ethical frameworks developed under surplus conditions, do not face in the same way.

[00:19:42]An ancient infant born during a catastrophic period into a group already at the limits of its survival capacity was born into a community whose ability to invest in that infant's survival was constrained in ways that had immediate and severe consequences.

[00:19:58]The social and emotional reality of ancient caregivers in this situation, the people who faced those constraints and lived with the decisions they made, is not accessible from the archaeological record in any direct way.

[00:20:10]But it is not difficult to imagine, and it is one of the most humanizing dimensions of understanding ancient catastrophic periods.

[00:20:19]What makes the question of worst birth timing ultimately so interesting is that it forces the examination of something that most discussions of ancient life avoid confronting directly.

[00:20:30]The enormous variance in individual experience within the species across time.

[00:20:35]Ancient humans living during productive stable periods, the African humid at its peak, the resource-rich periods of the early post-glacial warming, the millennia of relatively stable climate that preceded the most severe glacial advances, were not living lives of ease by modern standards, but they were living lives that were manageable by the standards of ancient human capacity.

[00:21:01]Ancient humans living during the worst catastrophic periods were living lives where the normal baseline of ancient difficulty was compounded by factors that pushed survival to the limit of what was biologically and socially possible.

[00:21:15]Being born during one of the catastrophic periods examined in this video meant arriving into a version of ancient life that was qualitatively different from the baseline.

[00:21:24]More desperate, more resource constrained, more socially stressed, and operating with smaller margins for the inevitable errors and bad luck that ancient life routinely involved.

[00:21:37]It meant that the probability of surviving infancy was lower. The probability of surviving childhood was lower, and the probability of reaching reproductive adulthood was lower than it would have been for a contemporary born into better times.

[00:21:51]And yet, the species survived all of these periods.

[00:21:55]Survived Toba, survived the glacial maximum, survived the Younger Dryas, survived the Saharan desertification.

[00:22:04]The populations that came through these catastrophic periods were smaller, sometimes dramatically smaller, than those that preceded them.

[00:22:13]The genetic bottlenecks visible in modern human DNA are the signature of those reductions.

[00:22:19]But, the survival of the species through the worst periods in its history is a testament to the adaptive capacity, social cohesion, and accumulated knowledge that ancient humans brought to exactly the conditions most likely to defeat them.

[00:22:34]The infants born during the worst periods who survived, who were carried through volcanic winters by caregivers who refused to stop, who were nursed through droughts by mothers running on insufficient calories, who were kept warm through glacial winters by communities that maintained fire and shelter and collective commitment to the group's continuation, those infants grew up to be the people who rebuilt populations, who transmitted knowledge across the catastrophic interval, who ensured that the next generation had the accumulated wisdom of people who had survived the worst.

[00:23:07]The worst time to be born as an ancient human was also therefore the time that produced some of the most resilient survivors in the entire history of the species. The timing was catastrophic.

[00:23:18]The people who made it through anyway were extraordinary.