Humans are a tropical species. We’ve lived in warm climates for most of our evolutionary history, which may explain why so many of us spend the winter huddled under a blanket, holding a jug and dreaming of summer.
In fact, all monkeys that exist live in the tropics. The oldest known fossils of the human lineage (hominids) come from here Central and East Africa. Hominids spreading northward to higher latitudes faced cold temperatures for the first time, shorter days that shortened the time to forage, snow makes hunting difficult Y an icy wind that exacerbated the loss of body heat.
Given our limited adaptation to cold, how come our species has come to dominate not only the ancestral warm lands, but all regions of the planet? The answer lies in our ability to develop complex cultural solutions to life’s challenges.
The first indications of the presence of hominids in Northern Europe come true Happisburgh, in the county of Norfolk, in the east of England, where footprints and stone tools have been found dating back 900,000 years. There was then a preponderance coniferous forests accompanied by cold winters similar to those in southern Scandinavia today. The data doesn’t seem to indicate that the hominids stayed in place for long periods of time, suggesting they haven’t had a chance to physically adapt.
How these hominoid primates survived the harsh conditions so different from those in their remote African homelands remains a mystery. There are no caves or remains of shelters in the area. The Happisburgh artifacts are simple, indicating the absence of complex technology.
Evidence for the existence of Deliberate bonfires at that time are controversial. The tools to make clothing adapted to the body and resistant to the weather they do not appear in Western Europe until nearly 850,000 years later. Many animals migrate to avoid seasonal cold, but Happisburgh humanoids they would have to move about 500 miles south for the difference to be significant.
It’s hard to imagine these creatures survived the old Norfolk winters without fire or warm clothing. However, the fact that there would be hominids that far north it means they had to find a way to withstand the cold, so who knows what archaeologists will find in the future.
The Boxgrove Hunters
Sites of more recent settlements, such as Boxgrove in West Sussex, southern England, provide further clues to how ancient hominids survived northern climates. The Boxgrove site it dates back to nearly 500,000 years ago, when the climate deteriorated into one of the coldest periods in human history.
We have strong evidence for that that hominids hunted animals, from bone cuts to a horse’s scapula, probably pierced with a wooden spear. These findings are consistent with studies of today’s hunter-gatherer populations, which show this those who live in colder areas rely more on the animals they hunt than those who live in warmer climates. The meat is rich in calories and fats necessary to withstand the cold.
Fossil tibia of a boxgrove hominid It is robust compared to modern humansindicating that it belonged to a tall and stocky individual. the largest organs of relatively short limbs reduce heat loss by minimizing surface area.
The optimal shape to prevent heat loss is the bulb. Therefore, animals and people from cold climates come as close as possible to it. Also, there is clearer evidence of it by then the existence of bonfires.
Cold weather specialists
The neanderthals, the inhabitants of Eurasia lived in glacial climates between about 400,000 and 40,000 years ago. Compared to their African predecessors and to us, they had that short, stout limbs and broad, muscular torsos that can produce and retain heat.
However, his knobbly face and hooked nose are the opposite of what might be considered adaptive in an ice age. Like Japanese macaques living in cold regions and lab rats raised in cold temperatures, current humans in cold climates they usually have a relatively high and narrow nose and broad and flat cheekbones.
computer simulations of ancient skeletons indicate that Neanderthal noses were more efficient than those of earlier species, adapted to higher temperatures, in retaining heat and moisture. It seems that the internal structure is just as important as the overall size of the respiratory organ.
Even with their cold-adapted physiques, Neanderthals remained a hostage to their tropical lineage. For instance, they lacked the thick fur of other mammals from Glacier Europe, such as woolly rhinoceroses or musk oxen. Instead, they developed a complex culture for survival.
We have archaeological evidence that they made clothes and built shelters of animal skins. The remains that show they cooked and used fire to create birch tar-based glue to create tools that showed advanced control over this source of heat.
The statement is more controversial some archaeologists that the bones of the first Neanderthals from the site of the Gorge of the bones, in Atapuerca, 400,000 years old, show seasonal deterioration due to the slowing down of metabolism to hibernate. The authors claim that the bones show disrupted growth and healing cycles.
Only a few primate species hibernate, such as some lemurs from Madagascar and the small African bushbaby, as well as the pygmy slow lorises of northern Vietnam.
This could suggest that humans can also hibernate. But most of the species that do it have a small body, with exceptions like bears. Humans are probably too big for that.
good for everything
The first fossils of the line homo sapiens They date back 300,000 years ago and come from Morocco but we didn’t leave Africa until about 60,000 years ago to colonize all corners of the planet. This makes us relatively newcomers to most of the habitats we currently occupy. In the thousands of years since, the inhabitants of icy places have biologically adapted to their environment, albeit on a small scale. A well-known example of this adaptation is that in areas with little solar radiation the homo sapiens develop light skin tones, better for synthesizing vitamin D. The genomes of today’s Greenlandic Inuit demonstrate their physiological adaptation to a high-fat marine diet, beneficial in cold environments. A more direct proof is provided by the DNA of 4000 year old hair preserved in the Greenlandic permafrost. The hair contains evidence of genetic changes that led to a stocky body shape that maximized heat production and retention, much like the Boxgrove hominin with only one tibia remaining.
Our tropical heritage means we still couldn’t live in cold places if we hadn’t developed ways to withstand the temperatures. For example the traditional inuit parkawhich provides better insulation than the Canadian Army’s modern winter uniform.
The human ability to adapt through behavior has been critical to our evolutionary success. Even compared to other primates, human physical adaptation to climate is slower. Behavioral adaptation is faster and more flexible than biological. Man is the ultimate of adaptability, and we thrive in almost every ecological niche possible.
Laura Bok is Assistant Professor of Evolutionary Anthropology at Liverpool John Moores University.
Kyōko Yamaguchi is senior lecturer in human genetics at Liverpool John Moores University.
This article was originally published on The conversation.
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