Feces fossils reveal ancient Indians’ diet

A new analysis of fossil feces from an Arizona cave reveals what ancient Native Americans ate.

The findings, reported in the August issue of Current Anthropology, shows that prehistoric hunter-gatherers in the Southwest lived on a diet remarkably high in fiber, low in fat, and consisting largely of foods with extremely low glycemic indices. That diet alone, the researchers say, could have been enough to fix fat-hoarding genes in place.

Keith Johnson, an archaeologist at California State University, Chico, directed excavations at Antelope Cave, in northern Arizona, that collected 20 human coprolites that provided a wealth of dietary data. Analysis suggests a diet dominated by maize and high-fiber seeds from sunflowers, wild grasses, pigweed and amaranth. These were usually ground into a fine flour and often showed signs of having been cooked. The researchers also found bones from small mammals, likely rabbit.

The report contradicts scientific speculation that the high diabetes rate among Native Americans may have roots in the evolutionary past. The foods consumed at Antelope Cave have very low glycemic indices, the measure of how fast a food causes blood sugar to increase. Recent research suggests that foods with high GIs may increase risk of obesity and diabetes. eurekalert.org

Cockroaches have split-second escape trick

Cockroaches, a new study finds, are brilliant escape artists.

A roach can flip under a ledge by swinging its body around like a pendulum and hanging on underneath. It uses hooklike claws to hold on firmly.

The movement occurs in milliseconds, too fast for the human eye to process. To the naked eye, it appears as if the cockroach has disappeared.

“It was a serendipitous discovery,” said Robert J. Full, a biologist at the University of California, Berkeley, and an author of the study, published in the journal PLoS One. “We were actually studying how these animals cross gaps.”

Brian McRae, a Berkeley undergrad who is also listed as an author, was working on the project and noticed that the cockroaches disappeared at the end of a ledge.

A closer look at video recordings revealed that they ran full speed toward the end and then dived off, grabbing the edge with their claws (at times using a single leg).

This may be why “sometimes when we’re chasing them they are just gone,” Full said. New York Times

Urban vegetation more ‘green’ than thought

Trees, bushes and other greenery growing in the concrete-and-glass canyons of cities can reduce levels of two of the most worrisome air pollutants by eight times what was previously believed, a new study by Britain’s Engineering and Physical Sciences Research Council has found. A report on the research appears in the ACS journal Environmental Science & Technology.

The study concluded that judicious placement of grass, climbing ivy and other plants in urban canyons can reduce the concentration at street level of nitrogen dioxide by as much as 40 percent and microscopic particulate matter by 60 percent, much more than previously believed

The authors even suggest building plant-covered “green billboards” in these urban canyons to increase the amount of foliage. Trees were also shown to be effective, but only if care is taken to avoid trapping pollutants beneath their crowns. American Chemical Society