To the bafflement of birders, yellow-shafted flickers (Colaptes auratus auratus) sometimes sport red or orange wing feathers.

Scientists have suggested that the birds, which inhabit eastern North America, might be products of genetic variation affecting the carotenoid pigments that produce their flight-feather colors. Alternatively, the birds might be hybrids from mixing with a subspecies that lives in the west, red-shafted flickers (Colaptes auratus cafer). Despite decades of study, no clear-cut explanation has emerged.

It turns out that diet may be to blame. Jocelyn Hudon of the Royal Alberta Museum in Canada and her colleagues tested the red flight feathers from two yellow-shafted flickers and found traces of rhodoxanthin, a deep red pigment found in plants, and a potential metabolite. This suggests that the birds’ bodies break down rhodoxanthin — a clue that the pigment enters the body through food. Spectral and biochemical tests of feathers from museum collections also point to rhodoxanthin and suggest that the pigment may mess with yellow carotenoid production as well.

Yellow-shafted flickers probably pick up the red pigment when they eat berries from invasive honeysuckle plants, which contain the ruby pigment and produce similar red hues in other birds, the researchers write October 12 in The Auk. The plants also happen to produce berries just around the time that flickers molt their flight feathers.

The Schiaparelli Mars lander, missing in action since its October 19 descent, dinged the surface of the Red Planet. A black spot framed by dark rays of debris mark the lander’s final resting place, the European Space Agency reports online October 27. Its parachute, still attached to the rear heat shield, lies about 1.4 kilometers to the south, new images from the Mars Reconnaissance Orbiter show. The front heat shield, ejected about four minutes into the descent, sits roughly 1.4 kilometers to the east of the impact site.

Radio contact with Schiaparelli was lost about 50 seconds before its planned landing. Early analysis of data from the lander indicate that the parachute was jettisoned prematurely and that the landing rockets shut off just a few seconds after igniting. Engineers with ESA’s ExoMars mission are still analyzing that data to understand what went wrong.

Below most volcanoes, Earth packs some serious deep heat. Mount St. Helens is a standout exception, suggests a new study. Cold rock lurks under this active Washington volcano.

Using data from a seismic survey (that included setting off 23 explosions around the volcano), Steven Hansen, a geophysicist at the University of New Mexico, peeked 40 kilometers under Mount St. Helens. That’s where the Juan de Fuca tectonic plate releases fluids due to intense heat and pressure as it descends beneath the North American plate. Those fluids rise and trigger melting in the rock above, fueling an arc of volcanoes that line up like lights on a runway. All except for Mount St. Helens, which stands apart about 50 kilometers to the west. Still, Hansen and colleagues expected to see a heat source under Mount St. Helens, as seen at other volcanoes.
Instead, thermal modeling revealed a wedge of a rock called serpentinite that’s too cool to be a volcano’s source of heat, the researchers report November 1 in Nature Communications. “This hasn’t really been seen below any active arc volcanoes before,” Hansen says.

This odd discovery helps show what the local crust-mantle boundary looks like, but raises another burning question: Where is Mount St. Helens’ heat source? Somewhere to the east, suggests Hansen. Exactly where, or how it reaches the volcano, remains a cold case.

Editor’s Note: this article was revised on January 4, 2017, to note how the Juan de Fuca tectonic plate fuels the chain of volcanoes.

Global emissions of carbon dioxide won’t increase much in 2016 despite overall economic growth, newly released bookkeeping suggests. The result marks a three-year-long plateau in the amount of CO2 released by human activities, scientists from the Global Carbon Project report November 14 in Earth System Science Data.

The group’s projected rise in CO2 emissions of 0.2 percent for 2016 is far lower than the rapid emissions growth of around 2.3 percent annually on average from 2004 through 2013. Emissions increased by about 0.7 percent in 2014 over the previous year and remained largely flat in 2015.

China is largely responsible for the emissions slowdown, the researchers write. The country is the world’s largest carbon dioxide emitter and is projected to reduce its CO2 emissions by 0.5 percent this year.

SAN ANTONIO — A roughly 3,000-year-old cemetery on Israel’s coast is providing an unprecedented look at burial practices of the Philistines, a mysterious population known from the Old Testament for having battled the Israelites.

Work at the Ashkelon cemetery from 2013 to 2016 has uncovered remains of at least 227 individuals, ranging from infants to older adults. Only a small section of the cemetery has been explored. Archaeologist and excavation director Adam Aja of the Harvard Semitic Museum estimates that approximately 1,200 people were interred there over a span of about 100 years.
“For the first time, we have found a formal Philistine cemetery,” Aja said November 18 at the annual meeting of the American Schools of Oriental Research. Aja and his colleagues first announced having found the Philistine graveyard on July 10. He was among several researchers to present their latest findings about the cemetery at the meeting.

Despite the new discoveries, the geographic origins of the Philistines remain unknown, Aja said. It’s also unclear how early Philistines reached the Middle East or how much their culture changed by the time they started burying their dead at Ashkelon.

Philistine burial practices have been discussed and debated for about a century. Other ancient Philistine sites in Israel, also identified in ancient texts, have yielded individual graves and small-scale burial grounds.

At Ashkelon, the dead were interred in several ways. Most individuals were placed in shallow pits, often with pairs of jugs or storage containers near the bodies. Some pits contained a person’s remains that had been buried on top of one or more previously interred bodies. Bronze earrings, bracelets, rings and other jewelry adorn most skeletons of children and women. Several pit graves of male skeletons include ornamental beads or engraved stones.

One grave holds a set of iron arrows near a man’s hip. A quiver probably once held the arrows at the man’s side, Aja suggested.
Researchers also uncovered ashes and bone fragments from six human cremations in sealed jars placed in pit graves.

At least eight stone burial chambers capped with stone slabs were also found. The largest chamber held skeletons of 23 individuals. These burial chambers were aligned in three rows that ran parallel to the coast, Aja said.

Tapered storage jars found in pit graves and burial chambers were influenced by pottery of the Canaanites, a nearby population along the Mediterranean coast, said team member Janling Fu of Harvard University.

Fu suspects the excavation is located at the cemetery’s edge. Considerable space between some burials suggests denser clusters of grave sites lie nearby, he proposed, raising the prospect of learning much more about how the Philistines treated their dead.

Although the excavation is in its early stages, it’s clear that Philistines buried at Ashkelon show signs of physiological stress, reported bioarchaeologist and team member Sherry Fox of Eastern Michigan University in Ypsilanti. Many individuals’ teeth have signs of growth interruptions caused by fever, malnutrition or a range of possible biological disorders, she said.

Relatively short average heights for people buried at Ashkelon — about 5 feet, 1 inch for men and 4 feet, 10 inches for women — also fit a scenario of biological stress, Fox said. Short stature and minimal height differences between men and women occur with population-wide stresses such as malnutrition, she said.

The Philistines were a famously combative crowd. Archaeologist Eric Meyers of Duke University, who was not a member of the Ashkelon team, wondered if at least some of those buried at Ashkelon had been killed in battles or fights. But no head injuries or other skeletal signs of violent encounters appeared among the dead at Ashkelon, Fox said. Neither did any skeletons contain evidence of tumors or cancers.

If DNA can be extracted from the Ashkelon skeletons, scientists may get a glimpse of where the Philistines originally came from. Evolutionary geneticist Johannes Krause of the Max Planck Institute for the Science of Human History in Jena, Germany, is currently directing efforts to retrieve genetic sequences from the Ashkelon bones.

“Our work has only just begun,” Aja said.

The first normally solitary spider to win Dad of the Year sets up housekeeping in a web above his offspring and often ends up as their sole defender and single parent.

Moms handle most parental care known in spiders, says Rafael Rios Moura at the Federal University of Uberlândia in Brazil. But either or both parents care for egg sacs and spiderlings in the small Manogea porracea species he and colleagues studied in a eucalyptus plantation. The dad builds a dome-shaped web above the mom’s web, and either parent will fight hungry invaders looking for baby-spider lunch. In webs with no parents, only about four spiderlings survived per egg sac. But with dad, mom or both on duty, survival more than doubled, the researchers report in the January 2017 Animal Behaviour.
“To the best of my knowledge, there really aren’t other examples where male spiders step up to care for young or eggs,” says Linda Rayor of Cornell University, who has studied spider maternal care. In a group-living Stegodyphus species, some of the males in a communal web will attack intruders, but Manogea dads do much more. They switch from solitary life to a dad-web upstairs, brush rainwater off egg sacs and share defense, sometimes at the cost of their own lives.
Many male web-building spiders stop feeding as adults because they’re out searching for mates instead of catching food with their web, Moura says. Manogea males, however, stick with a female they mated with and build a new food-catching web. Now Moura would like to know whether such commitment makes males unusually choosy about females, he says.

To predators, females “must be very delicious,” Moura says. In the wild he found that many females disappeared, probably eaten, by the end of the breeding season, leaving dads as the sole protector for 68 percent of the egg sacs.

That high female mortality could have been important for evolution of the dads’ care-taking, says behavioral ecologist Eric Yip of Penn State. Just why this species has such high female mortality puzzles him, though. Females, geared up for egg-laying, have rich nutrient stores. Yet, he says, “that’s generally true for all spiders — that females are going to be more nutritious and males are going to be mostly legs.”

A seahorse’s genetic instruction book is giving biologists a few insights into the creature’s odd physical features and rare parenting style.

Researchers decoded a male tiger tail seahorse’s (Hippocampus comes) genome and compared it to the genomes of other seahorses and ray-finned fishes. The analysis revealed a bevy of missing genes and other genetic elements responsible for enamel and fin formation. The absence of these genes may explain their tubelike snouts, small toothless mouths, armored bodies and flexible square tails, the team reports online December 14 in Nature.

Although H. comes may be short a few genes, the seahorse has a surplus of other genes important for male pregnancy — a trait unique to seahorses, sea dragons and pipefish. These genetic differences suggest the tiger tail seahorse has evolved more quickly than its relatives, the researchers conclude.

Famous footprints of nearly 3.7-million-year-old hominids, found in 1976 at Tanzania’s Laetoli site, now have sizable new neighbors.

While excavating small pits in 2015 to evaluate the impact of a proposed field museum at Laetoli, researchers uncovered comparably ancient hominid footprints about 150 meters from the original discoveries. The new finds reveal a vast range of body sizes for ancient members of the human evolutionary family, reports an international team led by archaeologists Fidelis Masao and Elgidius Ichumbaki, both of the University of Dar es Salaam in Tanzania.
A description of the new Laetoli footprints appears online December 14 in eLife.

Scientists exposed 14 hominid footprints, made by two individuals as they walked across wet volcanic ash. More than 500 footprints of ancient horses, rhinos, birds and other animals dotted the area around the hominid tracks. Like previously unearthed tracks of three individuals who apparently strode across the same layer of soft ash at the same time, the latest footprints were probably made by members of Australopithecus afarensis, the team says. Best known for Lucy, a partial skeleton discovered in Ethiopia in 1974, A. afarensis inhabited East Africa from around 4 million to 3 million years ago.

All but one of the 14 hominid impressions come from the same individual. Based on footprint dimensions, the researchers estimate that this presumed adult male — nicknamed Chewie in honor of the outsized Star Wars character Chewbacca — stood about 5 feet 5 inches tall and weighed nearly 100 pounds. That makes him the tallest known A. afarensis. The team calculates that the remaining hominid footprint was probably made by a 4-foot-9-inch female who weighed roughly 87 pounds. Stature estimates based on the other three Laetoli footprint tracks fall below that of the ancient female.

Lucy lived later than the Laetoli crowd, around 3.2 million years ago, and was about 3 ½ feet tall.
If Laetoli’s five impression-makers were traveling together, “we can suppose that the Laetoli social group was similar to that of modern gorillas, with one large male and a harem of smaller females and perhaps juveniles,” says paleontologist and study coauthor Marco Cherin of the University of Perugia in Italy.

Chewie’s stature challenges a popular assumption that hominid body sizes abruptly increased with the emergence of the Homo genus, probably shortly after A. afarensis died out, Cherin adds.

The new paper presents reasonable stature estimates based on the Laetoli footprints, but “we don’t have a firm idea of how foot size was related to overall body size in Australopithecus,” says evolutionary biologist Kevin Hatala of Chatham University in Pittsburgh. Masao’s group referred to size data from present-day humans to calculate heights and weights of A. afarensis footprint-makers. That approach “could lead to some error,” Hatala says.

Stature estimates based on footprints face other obstacles, says paleoanthropologist Yohannes Haile-Selassie of the Cleveland Museum of Natural History. For instance, some tall individuals have small feet and short folks occasionally have long feet. It’s also unclear whether the new footprints and those from 1976 represent a single group, or if some smaller footprints were also made by males, Haile-Selassie adds. Cherin’s proposal that large A. afarensis males controlled female harems “is a bit of a stretch,” Haile-Selassie says.

The new report doesn’t document surprisingly large size differences among members of Lucy’s kind, Haile-Selassie adds. A. afarensis fossils previously excavated in Ethiopia include a partial male skeleton now estimated by Haile-Selassie and his colleagues to have been only about three inches shorter than Chewie’s reported height (SN: 7/17/10, p. 5).

People hunted and foraged year-round in the thin air of China’s Tibetan Plateau at least 7,400 to 8,400 years ago, a new study suggests. And permanent settlers of the high-altitude region might even have arrived as early as 12,000 to 13,000 years ago.

Three lines of dating evidence indicate that humans occupied the central Tibetan Plateau’s Chusang site, located more than 4,000 meters above sea level, at least 2,200 years earlier than previously thought, say geologist Michael Meyer of the University of Innsbruck in Austria and colleagues. Their report, published in the Jan. 6 Science, challenges the idea that the Tibetan Plateau lacked permanent settlers until farming groups arrived around 5,200 years ago.、
“Hunter-gatherers permanently occupied the Tibetan Plateau by around 8,000 years ago, which coincided with a strong monsoon throughout Asia that created wet conditions on the plateau,” Meyer says.

These early permanent residents hunted animals such as wild yaks and foraged for edible plants, including berries from sea buckthorn shrubs, in nearby river valleys at elevations more than 3,600 meters above sea level, Meyer suspects. Brief, summer forays to Chusang would have been difficult for people living below 3,300 meters above sea level, he adds. Even when mountain passes were clear of heavy snowfall and expanding valley glaciers, round trips from low altitudes to the central Tibetan Plateau would have taken 41 to 70 days, Meyer’s team estimates.

Researchers discovered Chusang in 1998. The site consists of 19 human hand- and footprints on the surface of a fossilized sheet of travertine, a form of limestone deposited there by water from a hot spring.
The new age estimates for Chusang come from three measures: the decay rate of forms of radioactive thorium and uranium in travertine sampled in and around the prints; determinations of the time since quartz crystals extracted from the travertine were last exposed to sunlight; and radiocarbon measures of sediment and microscopic plant remains found on the travertine slab’s surface.
Signs of long-term camping at Chusang have yet to turn up, but extensive excavations of the site have not been conducted, Meyer says. His group found chipped rocks and other stone tool‒making debris at two spots near Chusang’s hot springs. These finds are undated.

Previous research has suggested that hunter-gatherers occasionally reached the Tibetan Plateau’s northern edge by around 12,000 years ago (SN: 7/7/01, p. 7), and again from about 8,000 to 6,000 years ago, says archaeologist Loukas Barton of the University of Pittsburgh, who wasn’t involved in the study. But the new discoveries at Chusang may not necessarily point to permanent residence there. Those early arrivals likely spent a single summer or a few consecutive years at most on the plateau, Barton says. “That would not constitute a peopling of a region any more than our 1969 visit to the moon did,” he says.

Archaeological finds indicate that human populations expanded on the Tibetan Plateau between around 5,200 and 3,600 years ago, Barton says. Those groups cultivated barley and wheat at high altitudes and herded domesticated sheep and perhaps yaks, he says.

Before that time, Chusang might have supported a year-round occupation, says archaeologist David Rhode of the Desert Research Institute in Reno, Nev., who wasn’t involved in the study. But the site could easily have been occupied seasonally, he says. Unlike Meyer, Rhode estimates that Chusang was about a two-week walk from some lower-altitude campsites. “That’s not far at all for a human forager.”

New dates for Chusang also raise the possibility that rare gene variants that aid survival in high-altitude, oxygen-poor locales first evolved among hunter-gatherers on the Tibetan Plateau, Meyer says. But both Barton and Rhode doubt it.

Heroin cure works

[T]he drug methadone appears to have fulfilled its promise as an answer to heroin addiction. Some 276 hard-core New York addicts … have lost their habits and none have returned to heroin — a 100 percent success rating. Methadone, a synthetic narcotic, acts by blocking the euphoric effect of opiates. Addicts thus get nothing from heroin and feel no desire to take it. — Science News. February 4, 1967.

UPDATE:
The U.S. Food and Drug Administration approved methadone as a treatment for opiate addiction in 1972 but quickly recognized that it was no panacea. That same year, policy makers worried that methadone would produce addicts — as patients got high off the treatment itself (SN: 10/28/72, p. 277). Methadone can be deadly: In 2014, 3,400 people died of methadone overdoses. Although methadone is still used, drugs such as buprenorphine and naltrexone have joined the treatment arsenal for opiate addiction.