When 500,000 years from now our distant descendants or extraterrestrials scrutinize the layers of sediments to investigate the Earth’s past, they will find unusual evidence of the abrupt change that upended life half a million years before: chicken bones.
That conclusion was reached by a group of scientists, who searched for evidence that the expansion of human appetites and activity altered natural systems so radically as to usher in a new geological epoch called the Anthropocene, or “epoch of humans.”
In addition to these bones, there will be other revealing elements of the rupture operated in the mid-twentieth century on the planet: the sudden increase in CO2, methane and other greenhouse gases, radioactive remains of nuclear tests, the omnipresence of plastics and the spread of invasive species.
But the chicken bones could be one of the most reliable evidence, which also allows the story to be told from different angles.
For a start, They are the result of human action.
“The chicken we eat is unrecognizable compared to its ancestors or its wild counterparts,” explains Carys Bennett, geologist and lead author of a study published in the Royal Society Open Science journal.
“Their size, skeletal shape, bone chemistry and genetics are different,” he clarifies.
Its mere existence, in other words, is proof of humanity’s ability to manipulate natural processes.
The research therefore conferred on this poultry the rank of “marker species” of the Anthropocene.
– ‘Clear signal’ –
The origins of the modern broiler can be traced to the jungles of Southeast Asia, where its ancestor, the red jungle fowl (Gallus gallus), was first domesticated around 8,000 years ago.
For a long time, this species was prized for its meat and eggs, but only after World War II did it begin to be reared into the short-lived, portly creature sold in supermarkets around the world.
“Usually evolution takes millions of years to happen, but in this case it only took decades to get a new form of animal,” Jan Zalasiewicz, emeritus professor of paleobiology at the English University of Leicester, told AFP.
The Anthropocene Working Group that he chaired for more than a decade determined last year that the Holocene epoch — which began 11,700 years ago with the end of the last ice age — gave way to the Anthropocene in the mid-20th century.
Its conclusions will be presented this Tuesday and the Group is expected to identify a site that in its opinion conclusively demonstrates the impact of human beings.
The broiler chicken also supports that definition due to its ubiquity. In any corner of the planet where there are humans, remains of our species’ favorite source of protein can be found.
The Food and Agriculture Organization of the United Nations (FAO) assesses that there are currently some 33 billion chickens Worldwide.
The biomass of domestic chickens is more than three times higher to that of all species of wild birds together.
At least 25 million they are slaughtered daily, whether for chicken tikka from Indian Punjab, yakitori in Japan, poulet yassa in Senegal, or McDonald’s nuggets.
“Chickens are a symbol of how our biosphere has changed and is now dominated by human consumption and resource use,” continued Bennett, who was a researcher at the University of Leicester before working for People for Ethical Treatment in the Animals (PETA).
“The enormous number of discarded chicken bones around the world will leave a clear signal in the future geological record,” he said.