Climate change was rampant in the ancient past. So how did our primitive ancestors survive?

Early Earth was hardly static, and neither were its inhabitants. Ancient humans had none of the luxuries of modern technology, yet they outlived many other species on their blood-filled path to the top of the food chain. But what type of terrain and weather did they have to navigate during this journey? A new study sheds light.

New international research has revealed that early humans were not constrained to any single biome, and as the climate fluctuated — often between extremes — they had to adapt to a variety of land spaces and food resources.

The Earth was throwing an increasing number of climate tantrums over the past three million years, making it particularly hard for the budding genus Homo to attain stable footing. While we know how the success story ends, scientists don't know whether our ancestors managed to just adjust local environmental shifts, or if they actively sniffed out more stable environments with better resources.

To get to the bottom of this mystery, researchers compiled data from more than three thousand well-dated human fossils and archaeological sites, spanning six species of ancient humans. In addition, they modelled simulations to determine what kind of biomes they dwelled in during their time on the planet.

"For the archaeological and anthropological sites and corresponding ages, we extracted the local biome types from our climate-driven vegetation model. This revealed which biomes were favoured by the extinct hominin species H. ergaster, H. habilis, H. erectus, H. heidelbergensis, and H. neanderthalensis and by our direct ancestors – H. sapiens,” explains lead author Elke Zeller.

Interestingly, they found that the early groups, originating in Africa around 3 million years ago, preferred open areas such as savannahs and grasslands. Then came the Eurasia migration around 1.8 million years ago, where the H. erectus, H. heidelbergensis and H. neanderthalensis somehow managed to develop higher tolerances to other biomes, moving to the colder and much-less open temperate and boreal forests.

"To survive as forest-dwellers, these groups developed more advanced stone tools and likely also social skills”, notes Pasquale Raia, a co-author. All of these characteristics boomed with the advent of H. sapiens around two lakh years ago in Africa, making them the jack and master of all adaptation trades.

The team also found that we eventually chanced on areas with a ton of biome diversity, and everyone wanted to set up shop in these parts. This new preference undoubtedly played a huge role in human evolution and was likely a massive driver of socioeconomic development.

"What that means is that our human ancestors had a liking for mosaic landscapes, with a great variety of plant and animal resources in close proximity”, remarked Axel Timmermann, another co-author of the study.

This was apparent on even continental scales, and the researchers have thus suggested that the success of Homo sapiens might suggest that we might be specially equipped to exploit such heterogeneous biomes.

Even though humans are stressed constantly about the warming climate, rising oceans, and the unending plethora of daggers that climate change threatens to strike into our necks, it can be worthwhile to remember humans remain the masters of adaptation.

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