Philippa Kaur

The remains of fish teeth at an archaeological site in Israel appear to have been cooked with controlled heat rather than directly exposed to fire

Humans

14 November 2022

By Christa Lesté-Lasserre
Illustration of hominins cooking fishElla Maru / University of Tel Aviv
Microscopic changes in the enamel of ancient fish teeth indicate that humans may have been cooking fish in an earthen oven at least 780,000 years ago.
The findings provide the earliest evidence of actual cooking, as opposed to just throwing meat and bones into a fire, says Irit Zohar at the Steinhardt Museum of Natural History in Tel Aviv, Israel.
“We’ve developed a methodology that allows us to identify cooking in relatively low temperatures, as opposed to burning,” she says. “You cannot immediately correlate the control of fire with cooking unless you show that the food has been cooked.”Advertisement
Researchers have previously suggested that humans were cooking meat 1.5 million years ago, based on the discovery of charred animal remains. But that doesn’t necessarily mean people were heating food before eating it, says Zohar.
“Evidence of charred material doesn’t mean cooking,” she says. “It just means the food was thrown into the fire.”
Zohar and her colleagues studied a 780,000-year-old settlement in Gesher Benot Ya’aqov in Israel’s northern Jordan river valley. No human remains have been found there, but based on its age and the stone tools at the site, the inhabitants are most likely to have been Homo erectus.
The researchers noticed clumps of fish teeth – but no bones – around areas where hearths once burned. Most of the teeth belonged to two species of fish known for their nutritional value and good taste – the Jordan himri (Carasobarbus canis) and the Jordan barbel (Luciobarbus longiceps). So they wondered if the fish had been cooked at low heat, which would have made the bones softer and prone to disintegration while preserving the teeth.
To test their idea, Zohar and her team adapted a technique from human forensic investigations in which X-ray diffraction reveals the sizes of crystals in tooth enamel, which vary according to temperature.
The researchers carried out cooking and burning experiments on readily available black carp (Mylopharyngodon piceus), heating them at different temperatures up to 900°C (1650°F), and then examined the resulting crystal sizes in the tooth enamel. They also looked at crystal sizes in three fossilised teeth from 3.15-to-4.5 million-year-old Jordan barbel, which had probably never been exposed to high heat.
Zohar and her colleagues then collected 30 fish teeth from among the tens of thousands available at Gesher Benot Ya’aqov and compared their enamel structures with those of the previously tested teeth.

They found that the fish teeth from the human settlement had enamel structure patterns indicating that they had been exposed to temperatures of 200°C to 500°C (390°F to 930°F) and hadn’t been directly exposed to the fire. Combined with there being nearly no fish bones nearby and the teeth being discovered near a controlled fire source, the findings suggest that the fish were probably cooked whole, perhaps in an earthen oven, says Zohar.
Notably, the results reveal that humans weren’t just eating fish raw and throwing the heads into the fire, because the tooth enamel would have shown exposure to much higher temperatures, she says.
“Each parameter in itself doesn’t mean cooking, but each one fits together like a puzzle so that we can say, ‘OK, now we see that it’s correlated to cooking’,” says Zohar.
Fish are more nutritious, easier to digest and safer to eat when cooked, says Zohar. The fact that these populations were cooking their fish provides evidence of their advanced cognitive abilities, which were perhaps greater than many scientists have previously believed. “If they already knew how to control fire, then it’s just logical that they would use it for cooking,” she says.
Journal reference: Nature Ecology & Evolution, DOI: 10.1038/s41559-022-01910-z
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From the pioneering days of IVF to modern gene editing, Siddhartha Mukherjee’s ambitious book explores how far we have come in understanding the cell – and how far we still have to go

Humans

9 November 2022

By Jason Arunn Murugesu
In less than 50 years, the IVF process has gone from pioneering to commonplaceNevodka/Alamy
The Song of the Cell
Siddhartha Mukherjee (Bodley Head)
ON 25 July 1978, Louise Joy Brown was born at Oldham General Hospital in the UK. The first child to be born following IVF, she was called a miracle baby by some, a test-tube baby by others, and a representation of the “degeneration of Western morals” by at least one.
A hundred years earlier, Walther Flemming, a German scientist, coined the term chromatin, meaning coloured substance, while he … More

We are still struggling to account for consciousness. A new hypothesis by psychologist Nicholas Humphrey challenges the basis of the discussion and argues sentience isn’t what we think

Humans

9 November 2022

By Philip Ball
Why did evolution invest in giving humans so much feeling about their world?Jonathan Knowles/getty images
Sentience: The invention of consciousness
Nicholas Humphrey (Oxford University Press)
THERE is a shelf in my brain – and in my study too – where I store theories of consciousness, and this is where psychologist Nicholas Humphrey’s new book, Sentience, will reside. Each of these theories and hypotheses can seem compelling in the moment, especially given the confidence with which they tend to be presented. They are usually unlike each other; often, they are diametrically opposed.
For example, in Sentience … More

The number of people on the planet has hit a huge milestone at 8 billion, but fertility rates are falling fast in many countries, which means planning for an older population

Humans

| Leader

9 November 2022

Shutterstock/Artem Musaev
THERE are soon to be 8 billion of us and counting. Yet while the world’s population is still growing fast overall, in many countries, the numbers are declining or will do soon.
Take the three largest. The population of China will begin to fall soon and could halve by 2100. India’s will peak around 2050. And the US population would fall from the 2030s if not for immigration.
So there are two distinct issues to deal with: rapid population growth in some nations and population declines in others.Advertisement
Many see limiting population growth as vital for tackling various environmental catastrophes unfolding around the world, as we report on in our article “What will a population of 8 billion people mean for us and the planet?” Yet for wealthy Westerners to call for lower-income countries to control their populations simply in the name of protecting nature is hypocritical in the extreme, given that the rich have vastly larger environmental footprints. What’s more, there is often more than a whiff of racism to such calls.
That said, there are good reasons for fast-growing countries to try to limit further population growth, as discussed in our article “Tackling population growth is key to fighting climate change”, not least because rapid increases can lead to more poverty. What’s more, two of the key factors in lowering fertility rates are educating women and respecting their rights, which all countries should be doing anyway.
Declining populations can be seen as a good thing in some ways – less pressure on wildlife, more space and so on. But having fewer working-age people and more older people is a huge economic challenge.
Apart from increasing immigration, there is no sure-fire way to stem individual nations’ population decline. This means that, in many parts of the world, governments need to be readying care and pensions systems to cope with ageing populations.
These trends are highly predictable over the next few decades, so there is absolutely no excuse for failing to prepare. It is also hugely important to invest in health. An ageing population has much less impact if people remain healthy well into old age.

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What age do you really become an adult? And why it’s vital to knowThe age at which you are considered an adult differs around the world, but emerging research into the developing brain suggests we may have got the concept of adulthood all wrong. When do we really become a grown-up? More

The early adopters of the alphabet cared about their personal hygiene, judging by the inscription on the side of an ancient ivory comb

Humans

9 November 2022

By Colin Barras
An ancient ivory comb with an inscription about head liceDafna Gazit/Israel Antiquities Authority
The oldest readable sentence written using the first alphabet has been found on the side of an ivory comb. The words are carefully inscribed in letters 1 to 3 millimetres wide and take the form of a plea: “May this tusk root out the lice of the hair and the beard.”
Writing emerged in Mesopotamia and Egypt about 5200 years ago. These early writing systems were non-alphabetic: They generally used signs to represent words and syllables. The alphabet came later. It was probably invented in or near Egypt, with certain ancient Egyptian hieroglyphics being repurposed to form the familiar alphabetic letters – each of which represents a small unit of speech called a phoneme.
The earliest history of the alphabet is mysterious because of a lack of archaeological evidence. It isn’t even clear exactly when the alphabet was invented: Many researchers argue for a date around 3800 years ago, but there is some evidence the alphabet was in use as early as 4300 years ago. It is also largely unclear how people used the alphabet, because the earliest texts we have found are short and difficult to decipher. This is why the inscription on the ivory comb is so important.Advertisement
Yosef Garfinkel at the Hebrew University of Jerusalem and his colleagues unearthed the comb in 2016 at Tel Lachish, an archaeological site in southern Israel. It came from a level of the site dating back roughly 2700 years, but from the style of the writing engraved on the comb, Garfinkel’s team argues this particular artefact is about 1000 years older.

The writing comprised 17 letters, two of which were damaged. Crucially, they seem to form a complete and understandable sentence written in an ancient Canaanite language spoken at Tel Lachish. “This is the earliest sentence we have in the alphabet,” says Garfinkel. The previous oldest known sentence is about 400 years younger than the one on the comb.
Christopher Rollston at George Washington University in Washington DC says it is a significant discovery. “Early alphabetic inscriptions are generally very brief – just a handful of letters – and often consist of the name of a person or the name of an object,” he says. A few longer inscriptions exist from the same time period as the comb, but researchers have struggled to read them because it is unclear what the texts were about.
Rollston says it was easier for Garfinkel’s team to read the newly discovered inscription because it was carved on a comb that still carries bits of the exoskeletons of dead lice, offering clues about the text’s likely subject matter. “This does not change the fact that this is still a brilliant decipherment,” says Rollston.
He also finds it fascinating that the inscription is about ordinary life. “Throughout human history, lice have been a problem,” says Rollston. “We can only hope that this inscribed comb was useful in doing that which it says it was supposed to do: Root out some of these pesky insects.”
Journal reference: Jerusalem Journal of Archaeology, DOI: 10.52486/01.00002.4
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The United Nations has declared that the world’s population will pass 8 billion people on 15 November. Our growing numbers have a variety of implications, from health to the environment

Humans

8 November 2022

By Michael Le Page
Aerial view of Old Town Square in Prague, Czech RepublicEblis/Getty Images
On 15 November, the world will pass a major milestone, as the human population hits 8 billion for the first time. Of course, it is impossible to know exactly when we will reach this threshold, but the United Nations has chosen this date to mark the occasion, based on its modelling.
Coming just 11 years after the human population hit 7 billion, it might seem as if the number of people in the world is growing faster than ever. But, in fact, the growth rate … More