Prehistoric people were dairy farmers
Prehistoric people in Saharan Africa had dairy farming operations 7,000 years ago, a new study reports - an insight revealed by their pottery. Researchers performed isotope analysis on samples drawn from excavated pottery, and were able to identify organic residues that originated from dairy fat.
The findings appear in the current issue of the journal Nature. The researchers found that the pottery, from a site in Libya known as the Takarkori rock shelter, retained an abundance of carbon isotopes related to fats from ruminant animals, like dairy and adipose fats, said Julie Dunne, an archaeologist at the University of Bristol in England and the study's first author.
The analysis also indicates that the prehistoric dairy farmers were processing milk."We know that they were heating it, to make butters and so on," Dunne said. "We can't tell whether it was butter, cheese or yogurt, but we can tell they were processing it in the pots."
This makes sense, she said, because people at the time were probably lactose-intolerant, and processing would have helped them digest the dairy more easily. Rock art found throughout the region also offers hints that dairy might have been an important part of people's diet. "There are scenes of people and cattle, and the fact that they bothered to draw the udders - that's why it was thought so," Dunne said.In a few cases, there are even depictions of cows being milked. These images, however, could not be reliably dated.
The technology to perform the isotope analysis was developed over the last decade, "but nobody had thought to look at the pottery and check the organic residue," Dunne said.
How geckos stay on their sticky toes
Geckos have adhesive toe pads that allow them to cling to almost any surface with ease. Researchers now report that the mechanics of the geckos' stride help keep these pads clean, preserving their stickiness.
Writing in The Journal of the Royal Society Interface, Shihao Hu and his colleagues report that geckos are able to clean the microscopic foot hairs, called setae, on their toe pads by hyperextending their toes. "The scrolling motion generates the inertial force that dislodges particles," said Hu, a mechanical engineer who is now a postdoctoral researcher at Case Western Reserve University. The study was done as part of Hu's doctoral research at the University of Akron.
He and other researchers put small "shoes" on the geckos to prevent hyperextension and found that the self-cleaning rate was reduced by half. They studied Tokay geckos, the second-largest gecko species. Each microscopic foot hair on the Tokay is further split into hundreds of nanobranches, Hu said.
Because the gecko has so many contact points, it is able to stick to surfaces. Our own hands can't do this because "the real contact area between our hands and a surface is not significant enough," Hu said.
In a chorus of bleats, one sounds familiar
If you've heard one pygmy goat kid bleating, you've heard them all - unless, that is, you're a mother goat.
A new study reports that mothers can recognize the calls of their kids even after more than a year of separation.
In the wild, female goats tend to stay within their groups, while males disperse. For their study, researchers separated the goats after weaning, and found that the mothers remembered the calls of their offspring for seven to 13 months. The study appears in the journal Proceedings of the Royal Society B.
"Mothers responded more to their kids born the previous year than to newborn kids born to other mothers," said Elodie F Briefer, an evolutionary biologist at Queen Mary, University of London, and one of the study's authors.
Prehistoric people in Saharan Africa had dairy farming operations 7,000 years ago, a new study reports - an insight revealed by their pottery. Researchers performed isotope analysis on samples drawn from excavated pottery, and were able to identify organic residues that originated from dairy fat.
The findings appear in the current issue of the journal Nature. The researchers found that the pottery, from a site in Libya known as the Takarkori rock shelter, retained an abundance of carbon isotopes related to fats from ruminant animals, like dairy and adipose fats, said Julie Dunne, an archaeologist at the University of Bristol in England and the study's first author.
The analysis also indicates that the prehistoric dairy farmers were processing milk."We know that they were heating it, to make butters and so on," Dunne said. "We can't tell whether it was butter, cheese or yogurt, but we can tell they were processing it in the pots."
This makes sense, she said, because people at the time were probably lactose-intolerant, and processing would have helped them digest the dairy more easily. Rock art found throughout the region also offers hints that dairy might have been an important part of people's diet. "There are scenes of people and cattle, and the fact that they bothered to draw the udders - that's why it was thought so," Dunne said.In a few cases, there are even depictions of cows being milked. These images, however, could not be reliably dated.
The technology to perform the isotope analysis was developed over the last decade, "but nobody had thought to look at the pottery and check the organic residue," Dunne said.
How geckos stay on their sticky toes
Geckos have adhesive toe pads that allow them to cling to almost any surface with ease. Researchers now report that the mechanics of the geckos' stride help keep these pads clean, preserving their stickiness.
Writing in The Journal of the Royal Society Interface, Shihao Hu and his colleagues report that geckos are able to clean the microscopic foot hairs, called setae, on their toe pads by hyperextending their toes. "The scrolling motion generates the inertial force that dislodges particles," said Hu, a mechanical engineer who is now a postdoctoral researcher at Case Western Reserve University. The study was done as part of Hu's doctoral research at the University of Akron.
He and other researchers put small "shoes" on the geckos to prevent hyperextension and found that the self-cleaning rate was reduced by half. They studied Tokay geckos, the second-largest gecko species. Each microscopic foot hair on the Tokay is further split into hundreds of nanobranches, Hu said.
Because the gecko has so many contact points, it is able to stick to surfaces. Our own hands can't do this because "the real contact area between our hands and a surface is not significant enough," Hu said.
In a chorus of bleats, one sounds familiar
If you've heard one pygmy goat kid bleating, you've heard them all - unless, that is, you're a mother goat.
A new study reports that mothers can recognize the calls of their kids even after more than a year of separation.
In the wild, female goats tend to stay within their groups, while males disperse. For their study, researchers separated the goats after weaning, and found that the mothers remembered the calls of their offspring for seven to 13 months. The study appears in the journal Proceedings of the Royal Society B.
"Mothers responded more to their kids born the previous year than to newborn kids born to other mothers," said Elodie F Briefer, an evolutionary biologist at Queen Mary, University of London, and one of the study's authors.