Days after northern China emerged from flood, four provincial regions in the northwestern part of the country are facing a new challenge that has led them to activate level-IV emergency responses for drought. Experts warned of more severe droughts this year with the return of El Nino, but called for calm as these regions are frequently hit by drought and have accumulated rich experience.

Since June, drought has hit central and western Inner Mongolia, Gansu, Qinghai and Ningxia, with the amount of flowing water and the amount of water stored in reservoirs in this region lower than the same period in normal years, according to the Ministry of Water Resources on Wednesday.

The severe drought in the four provincial regions is also expected to continue to persist for a longer period, according to the ministry. China has a four-tier emergency response system for disaster relief, with Level IV being the lowest and Level I the highest.

In the Jinchuan district of Jinchang city in Gansu, corn cobs cannot even be seen across stretches of corn fields where corn stalks are evidently short and leaves are withered. In response, local departments have started a second round of irrigation to ensure arable land get sufficient water supply, China Central Television reported.

Jinchang city also mobilized drones for free to spray pesticides in farmers' corn and potato fields to prevent pests and disease and lower the losses of farmers. 

The Lanzhou Central Meteorological Observatory activated a yellow warning for drought at noon on Tuesday. It said the latest monitoring data shows the drought in the cities of Jinchang, Wuwei and Baiyin has become even more severe.

A drought relief expert who preferred not to be named told the Global Times on Wednesday that the four northwestern provincial regions are frequently hit by drought, so local departments are experienced in drought relief. In the end, the biggest impact in the region will be on animal husbandry.

The Gansu provincial emergency department called for efforts to guarantee the water supply for people's livelihoods and livestock. 

One day earlier on Tuesday the ministry said it had sent working groups and expert teams to the four provincial regions. 

The ministry has also urged local water management authorities to closely monitor the development of rain, water and drought, to scientifically divert water from conservancy projects and to adopt localized measures.

But according to the National Meteorological Center on Wednesday, in the next three days, there will be moderate to heavy rain in Qinghai, Gansu, western Sichuan, and also precipitation in Inner Mongolia. 

The drought relief expert said the rainfall should mitigate the regional drought but it still needs to be decided in how much degree it would ease the drought. 

Climate change experts have warned that the development of El Nino, a result of natural shifts in winds and ocean temperatures, is expected to contribute to global warming and increase the likelihood of temperature records being broken. It also brings heavier floods to some parts of the planet while drying others out.

In the period from late June to July 2009, 17 provinces in China suffered from severe drought due to a moderate El Ni?o event. Eastern Inner Mongolia, western Jilin Province, and western Liaoning Province also experienced extreme drought, experts said. 

An Asian elephant detected a 2.8-kilogram consignment of opium in Mengman township, Southwest China's Yunnan Province during a walk in the region. The case is under investigation by the local police, according to a People's Daily report on Tuesday.

Border police of Mengman township, Xishuangbanna Dai Autonomous Prefecture received a report recently that four wild Asian elephants were roaming around a village in the town. When the police arrived at the site, they found that one of the elephants stopped and carefully sniffed in an area of grass, and then used its trunk to toss a backpack out of the grass, while also making some "calls."

The police immediately checked the backpack and found the opium. The case is currently under further investigation.

The story triggered wide discussion among Chinese netizens, with the topic gaining more than 190 million clicks as of Tuesday morning on Chinese-twitter like Sina Weibo. Many netizens praised the elephant with its delicate sense of smell and said that it should be awarded with more fruits like bananas. Some called for more protection for "smart" elephants, mankind's "good friend."

China is considering holding degree holders who use artificial intelligence (AI) to ghostwrite their theses legally responsible. The draft of the Degree Law was submitted to the Standing Committee of the 14th National People's Congress, China's top legislature, for deliberation on Monday.

The draft lays out legal responsibilities for actions such as degree holders using or impersonating another's identity to gain admission qualifications, employing artificial intelligence to author thesis papers, and institutions granting degrees unlawfully, as reported by the media on Monday. 

Academic misconduct includes plagiarism, forgery, data falsification, using artificial intelligence to produce a thesis, impersonating another's identity to obtain admission qualifications, and securing admission qualifications and graduation certificates through illicit means like favoritism and cheating. The draft also addresses other illegal or irregular behaviors that, when exhibited during the study period, should prevent the awarding of a degree.

The draft states that if an individual who has already obtained a degree is found to have used illegal means to do so, the degree-granting institution must revoke the degree certificate. This decision should be made following a review by the degree evaluation committee.

Being infected with a parasite is usually not good news. Some of the critters can make you sick, and some will eventually kill you. And studies have found that when an animal has to deal with both a parasite and pollutants such as toxic heavy metals, the stressors add up.

But that isn’t true for Artemia brine shrimp in Spain, a new study finds. Infection with cestodes — a type of parasitic flatworm also known as tapeworms — results in an increased ability to survive in waters laced with toxic arsenic.
Marta Sánchez of the Spanish National Research Council in Seville has been studying the role of parasites in ecosystems. She and her colleagues were curious about the brine shrimp because they are key players in the ecosystem; they are eaten by many water birds, including flamingos, and can ferry pollutants and parasites into the birds. “Infected [brine shrimp] are more susceptible to predation by birds,” Sánchez notes, which contributes to pollutant levels in the birds.

When brine shrimp become infected with parasites, they turn red. This makes them especially attractive to birds not only because they are easier to see but also because birds are on the lookout for the carotenoid pigments responsible for the color. These pigments not only give a bird’s feathers their colors but they are also necessary for a healthy bird. “As birds cannot synthesize these pigments and they are a scarce resource in nature, they selectively search for them in their diet,” Sánchez says.
The red color also makes it easy for scientists to pick out infected brine shrimp. Sánchez and her colleagues collected brine shrimp from southwestern Spain’s Odiel and Tinto estuary, which is tainted with arsenic and other heavy metals from current and past mining activities. In the lab, the researchers separated the parasite-infected and uninfected brine shrimp and then ran tests to see how well they survived in arsenic-laced waters.

As the concentration of arsenic in the water increased, so did the number of brine shrimp that died. But more brine shrimp that were infected with cestodes survived than uninfected ones, the team reports March 3 in PLOS Pathogens. Then, curious about the effects of climate change, the researchers repeated their experiment with warmer water. Again, the parasites appeared to confer some level of protection to the brine shrimp.
It may not be obvious, but causing a quick death is not a good strategy for a parasite. That’s because a parasite needs its host to stay alive long enough for the parasite to reproduce, leave and find a new host. If the host dies too quickly, then the parasite dies with it. So for cestodes, giving brine shrimp some help in surviving polluted waters may be in the parasites’ best interest.

The results suggests that the cestodes help change the way the brine shrimp deal with pollutants and the resulting stress. When the researchers compared infected and uninfected brine shrimp, they found differences in the antioxidant defenses that protect an organism against the damaging effects of reactive oxygen species. “Infected individuals were better than uninfected individuals at coping under polluted conditions,” Sánchez says. Also, infected brine shrimp had higher amounts of lipid droplets that are thought to sequester toxins.

The researchers can’t say whether this beneficial relationship is restricted to this particular estuary in Spain. “What we can say,” Sánchez says, “is that the red coloration associated with tapeworm infections is something we have observed in many sites in different countries. Hence, we expect our results do represent what would be recorded at other localities.”

Brazil, now a poster child for mosquito-borne virus spread, was once a model for mosquito eradication.

“It was amazing,” says Dan Strickman, medical entomologist with the Bill and Melinda Gates Foundation. The Aedes aegypti mosquito, today identified by epidemiologists as one of the carriers of the Zika virus, was attacked in the 1930s with the simple tools then available. By 1965, the mosquito was certified as eradicated from Brazil and 17 other countries in the Americas (but not the United States). The feat took ferocious effort, but as the threat dwindled, so did money and the political will to stay vigilant.
Whether eradication would even be possible now is unclear. But the question of how to cope with Ae. aegypti has taken on new urgency as that mosquito species sweeps Zika virus through South and Central America and into parts of North America. Known as the yellow fever mosquito, Ae. aegypti can also spread dengue, chikungunya and West Nile viruses (SN: 6/13/15, p. 16).
It’s “the most difficult mosquito in the Americas to control,” says Michael Doyle, director of mosquito control for the Florida Keys. The mosquito’s resistance to major pesticides and its unusual biology foil many standard control measures. Some scientists have developed high-tech control approaches. Other specialists are going back to the basics to search for biological vulnerabilities that have been overlooked.
Casual slappers of mosquitoes tend to lump all of them into one annoying category, but there are 3,500 or so species, with a wide range of idiosyncrasies. Some species, for instance, don’t drink blood. As a group, though, mosquitoes are among the most dangerous animals on Earth, claiming more than 400,000 lives a year just from spreading malaria.

Researchers propose that several species might spread Zika, depending on location: Ae. hensilli was suspected in a previous outbreak on Yap in Micronesia and Ae. polynesiensis in French Polynesia. In the Americas, epidemiologists are watching two widespread invasives: the Asian tiger mosquito Ae. albopictus (SN: 6/29/13, p. 26) as well as the notorious Ae. aegypti.

A forest-dwelling form of Ae. aegypti, native to Africa, frequents tree holes and sucks blood from animals. The worldwide invaders, however, have become domesticated. “They bite almost exclusively humans; they live almost exclusively within feet of humans,” Doyle says.

For many mosquitoes, blood is for motherhood, usually one drink per batch of eggs. The insects meet everyday energy needs with plant sugars such as flower nectar. Ae. aegypti females, however, sip blood often, raising the chances of passing on disease. That’s because they’re unusually adept at extracting energy from blood instead of nectar, Laura Harrington, who studies mosquito biology at Cornell University, and her colleagues found.

A common way to fight bloodsuckers is spraying pesticides from trucks or aircraft. But spraying often does little to Ae. aegypti holing up in houses, resting on clothing in closets or hiding under beds. And don’t count on nighttime protection from bed nets. Ae. aegypti readily bite during the day.
To fight such a foe, crews start by trying to kill larvae before they reach vampire age. Mosquitoes generally go through their first life stage in water, and Ae. aegypti needs only a little containerful. So Doyle sends inspectors on house-by-house quests for stray minipools: in a bucket, a Fritos bag, old tires, a kayak and plant saucers by the dozens. And that could be in just one yard. His difficulties make a fine case study in how hard — and expensive — fighting a human-specialist mosquito can be.

The human-versus-mosquito battle isn’t all door-to-door. The company Oxitec, based in the United Kingdom, engineered male Ae. aegypti mosquitoes to carry genes that cause their offspring to die (SN: 7/14/12, p. 22). Using an old insect-control strategy, mass releases of dysfunctional males seduce wild females and, in time, shrink the problem population.

Experimental releases of Oxitec’s genetically modified Ae. aegypti males have reduced the size of mosquito populations by more than 80 percent in a test site of about 5.5 hectares in a suburb of Juazeiro, Brazil. The Brazilian government has approved these engineered mosquitoes for widespread use. Oxitec has applied for U.S. Food and Drug Administration approval to do a similar test in the Florida Keys. On March 11, the FDA released a draft statement predicting “no significant impact” to the environment from the test (SN Online: 3/11/16).

Efforts to genetically sterilize mosquitoes may improve with advances in CRISPR/Cas9 techniques to cut and paste genes (SN: 12/12/15, p. 16). And an advance in the genetics of sex determination last year opens new possibilities for refining sterile-male releases. What’s called an M factor determines maleness in certain insects, and for the first time in any mosquito, researchers determined the sequence of the genetic components of Ae. aegypti’s M factor. Manipulating it to produce entire generations of only males could have many uses, says Virginia Tech’s Zach Adelman.
In a different approach to reengineering mosquitoes ( SN: 7/14/12, p. 22 ), researchers with the international consortium called Eliminate Dengue are testing a nongenetically modified mosquito in Brazil among other places. Instead of wiping out a population, the goal is to reduce its disease-spreading power. Infection with a strain of Wolbachia , bacteria common in insects, can render these mosquitoes less likely to transmit dengue virus. A paper due out soon will show that the Wolbachia -carrying mosquitoes are also less likely than uninfected ones to transmit chikungunya, as well as  Zika, says Wolbachia project leader Scott O’Neill at Monash University in Melbourne, Australia.
Search for an Achilles’ heel
What interests Cornell’s Harrington are the undiscovered mosquito-fighting targets. Her lab studies courtship and reproduction in mosquitoes. “I really believe that’s where their Achilles’ heel is,” she says.

Courtship among Ae. aegypti is unusual and more complex than anyone had imagined, Harrington, her student Lauren Cator and colleagues reported in 2009. The scent of a human host attracts amorous male mosquitoes, which fly nearby until a female arrives looking for a blood meal. Male mosquitoes’ wide, feathery antennae pick up harmonic overtones of the whine of female wingbeats. The mosquitoes then synchronize one of the wingbeat overtones. “They’re singing to each other,” says Ethan Degner, a Harrington graduate student. Perhaps there’s a way to disrupt this courtship.

Another of the Harrington lab’s findings might be more immediately relevant. Conventional wisdom is that Ae. aegypti mosquitoes mate only once in their lives. Degner offered lab females a second chance to mate, but with a collaborating lab’s genetically engineered males that produce fluorescent red sperm. In lab conditions, a low percentage of females showed red in their reproductive tracts, indicating they mated twice, Degner and Harrington reported online February 15 in the American Journal of Tropical Medicine and Hygiene. This result agrees with observations of what looked like occasional second matings in the wild. With millions of dollars going into mass releases of sterile competitors to local fertile males, female willingness takes on new importance.

If biologists come up with some new way to eradicate Ae. aegypti, then humankind would have to decide whether to use it. Aside from moral questions, removing any species from an ecosystem can have unexpected risks and consequences. The weighing of arguments will differ species by species, even for mosquitoes. But the human-seeking form is a relative newcomer to the Americas. So in this era of Zika and other rampant mosquito-borne diseases, whether to blast this mosquito out of the hemisphere, should it ever be possible, might not be a difficult decision at all.

There must be something wrong with the guy who never leaves home, right? Maybe not — at least if that guy is a male spotted hyena. Males that stay with their birth clan, instead of taking off to join a new group, may simply be making a good choice, a new study suggests.

Spotted hyenas are a matriarchal society. Females are in charge. They rank higher than every male in the clan. And the females generally stay with the clan for their entire lives. But males face a choice when they reach two and a half years in age. They can stay with the clan, or they can leave and join a new clan.

Each choice has its pros and cons. Staying with the clan means that a male hyena keeps a place at the top of the male pecking order. He’ll probably have his mother around to help. But he’ll be limited in the number of females he can mate with, because many of the female hyenas won’t mate with him because they might be related. If he joins a new clan, the male hyena might have access to more females — and they might even be better than the ones in his home clan — but he’ll start with the lowest social rank and have to spend years fighting his way to the top.

Among most group-living mammal species, the guys that stay at home turn out to be losers, siring fewer offspring. But spotted hyenas, it appears, are an exception.

Eve Davidian of the Leibniz Institute for Zoo and Wildlife Research in Berlin and colleagues tracked 254 male spotted hyenas that lived in eight clans in Ngorongoro Crater in Tanzania throughout their lives, a study lasting 20 years. When these males reached the age of maturity, they left their clans to take a look at the other options available to them. Forty-one hyenas returned to their home clans, and 213 settled with new ones.

Even though the males that stayed at home probably had fewer potential breeding partners, they still managed to sire as many offspring as those males that left for greener pastures. Many mated at an earlier age, and they tended to mate with higher-ranking females than males that joined new clans. And both groups lived similar lengths of time, the researchers report March 18 in Science Advances.

The guys who stay at home, it seems, aren’t losers who couldn’t find better prospects elsewhere. They just found good enough prospects at home, where they are at the top of the social ladder — and have mom around to help them get access to food and females.

Seems like a good strategy — for hyenas, at least.

White dwarfs — the exposed cores of dead stars — are the last place astronomers expected to find an oxygen atmosphere. Yet that’s exactly what recently turned up, providing researchers a rare peek inside the core of a massive star and raising questions about how such an oddball could have formed.

Most stars die by gently casting the bulk of their gas into space, leaving behind a dense, hot core. Heavy elements such as carbon and oxygen sink to the core’s center while hydrogen and helium float to the surface. But a newly discovered white dwarf, about 1,200 light-years away in the constellation Draco, has no hydrogen or helium at its surface. Its atmosphere is instead dominated by oxygen, researchers report in the April 1 Science.
“We only found one, so it is a rare event,” says study coauthor Kepler de Souza Oliveira Filho, an astronomer at the Federal University of Rio Grande do Sul in Porto Alegre, Brazil. But, he says, “every theory must be able to explain all events, even the rare ones.”

Hydrogen and helium blanket most white dwarfs, hiding what lies beneath. Here, astronomers have “a window into the core of a star that we didn’t have before,” says Patrick Dufour, an astrophysicist at the University of Montreal.

While oxygen dominates this white dwarf’s atmosphere, neon and magnesium come in second and third — a clue that the original star was much bigger than our sun. Big stars can crank up their core temperatures high enough to fuse progressively heavier elements. A star between about six and 10 times as massive as the sun ends up with a core made of mostly oxygen, neon and magnesium — precisely what Filho and colleagues found. But there’s a problem: Such a white dwarf should be a bit heavier than our sun, and this newly discovered misfit appears to have about half as much mass.

A nearby stellar companion could have siphoned gas off the dying star, starving the white dwarf of mass, the researchers suggest. Thermonuclear excavation during the star’s end game could also lead to an underweight white dwarf. If enough hydrogen piled up on the core, it might have triggered a runaway nuclear explosion that shaved off the white dwarf’s outer layers.

While plausible, it’s hard to see how that could remove half of the white dwarf’s mass, Dufour says. “That’s very strange,” he says. “It could work, but I doubt it would leave a low-mass white dwarf.”
In 2007, Dufour and colleagues reported a similar strange sighting: several white dwarfs whose atmospheres were loaded with carbon instead of hydrogen and helium. Those also appeared to be missing some mass, he says, though the problem was found to lie not with the stars but with the mass estimates. The white dwarfs are heavier than initially thought, and Dufour now suspects that each one arose from a collision between two white dwarfs.

It’s too early to draw strong conclusions from a single oxygen-laden white dwarf. “There are lots of open questions before we can say that this changes our view of white dwarf evolution,” Dufour says. “This white dwarf might only be a freak…. Although often in science, it’s the exception that makes you understand a great deal later on.”

Antarctica’s meltdown could spur sea level rise well beyond current predictions. A new simulation of the continent’s thawing ice suggests that Antarctic melting alone will raise global sea levels by about 64 to 114 centimeters by 2100, scientists report in the March 31 Nature.

Adding Antarctic melt to other sources of sea level rise, such as the expansion of warming seawater and melting Greenland ice, the scientists predict that sea levels will rise 1.5 to 2.1 meters by the end of the century. That’s as much as double previous predictions that didn’t incorporate mechanisms that can expedite the Antarctic ice sheet’s collapse, though uncertainties remain, says study coauthor David Pollard, a paleoclimatologist at Penn State.
Predicting future sea level rise requires understanding how the oceans rose in the past. Scientists often glean ancient sea level rise by reconstructing the locations of ancient coastlines. But these coastlines can be a slippery target: Forces such as tectonic activity can cause Earth’s surface to rise and fall, obscuring the effects of past sea level rise. Depending on how much uplift obfuscated ancient sea level records — ranging from no uplift to massive uplift — the new prediction of 21st century sea level rise can differ by 35 centimeters or more.

A separate study also highlights the challenges of factoring changing coastlines into sea level rise predictions. Researchers estimate online April 2 in Geophysical Research Letters that groundwater depletion has caused the coasts of California and India to rebound upward, counteracting sea level rise in those regions by about 0.4 millimeters per year.

“I really would be happier if we had the luxury of doing the research on this without bothering the public until we have 95 percent confidence in an answer,”says Penn State glaciologist Richard Alley, who was not involved in either study. “Any single forecast is notably uncertain, but if we continue warming the world rapidly, the most likely outcome is a major event of large and rapid sea level rise.”

Two warm periods, one about 125,000 years ago and another about 3 million years ago, were particularly useful for Pollard and coauthor Robert DeConto, a geoscientist at the University of Massachusetts Amherst. Those bouts of warming shrank Earth’s ice sheets and boosted sea levels by several meters. Pollard and DeConto used these sea level records to fine-tune a computer simulation of how climate change affects the Antarctic ice sheet. The researchers then applied their calibrated simulation to current climate conditions and projected sea level rise thousands of years into the future.

Assuming that society takes no actions to curb greenhouse gas emissions, the simulation predicts that Antarctic melting will accelerate around 2050 as rising temperatures destabilize several keystone glaciers in West Antarctica. After 2100, Antarctica’s contribution to sea level rise will exceed 4 centimeters a year — more than 10 times the current rate from all sources.
Such severe sea level rise would reshape most of Earth’s coastlines, and the waters would rise even higher as time goes on, Pollard predicts. “Sea levels won’t peak until around 3,000 to 4,000 years from now,”he says. At that point, Antarctica will have raised global sea levels by about 20 meters.

The consequences of this long-term sea level rise will be dire, says Maureen Raymo, a marine geologist at Columbia University’s Lamont-Doherty Earth Observatory in Palisades, N.Y., who was not involved with the work. “I haven’t seen anyone mention the long, slowly unfolding refugee crisis that will only get worse as hundreds of millions [of people] are displaced worldwide,” she says.

Even top-caliber diamonds aren’t perfect. And their imperfections are finally settling a debate about the origins of the gem-quality diamonds used in jewelry.

Previously, scientists had an explanation only for how cloudy and impurity-ridden fibrous diamonds form. Those diamonds crystallize inside fluid pockets deep within the Earth that contain compounds called carbonates. Carbonate-containing impurities inside fibrous diamonds provide information about the diamonds’ origins. Gem diamonds typically don’t contain these impurities, so scientists argued over whether the gems formed under different conditions than fibrous diamonds.
After an exhaustive hunt, geochemists have at last found microscopic impurities within gem-quality diamonds. These flaws suggest that pretty and ugly diamonds form from the same kinds of carbonate-containing fluids, the researchers report in the June 1 issue of Earth and Planetary Science Letters. The finding may also offer insights into the history of plate tectonics.

The work “gives us the first strong constraint on how gem diamonds grow,” says Thomas Stachel, a petrologist at the University of Alberta in Canada who was not involved in the research. “People had proposed various explanations for how these diamonds form, but it seems diamond formation is less diverse than we thought.”

Diamonds are made up of carbon atoms. At the pressures and temperatures found in the deep Earth, these carbon atoms can form a crystal structure. Rising magma then carries the crystals to the surface.

The type of diamonds prized for jewelry formed as early as 3.5 billion years ago. Fibrous diamonds date back only a few million years and formed more quickly. That quick creation trapped bits of surrounding material inside the crystal structure. Those inclusions suggest that these diamonds formed from the carbon atoms in carbonate-containing fluids. Gem-quality diamonds formed more slowly and usually don’t contain any inclusions. “That’s why they’re gem quality —there’s nothing in them,” says study coauthor Brooke Matat Jablon, a geochemist at the Hebrew University of Jerusalem.
Jablon and geochemist Oded Navon, also at the Hebrew University, hunted for inclusions in diamond gemstones. The researchers finally found what they were looking for in diamonds that are symmetrical across a central boundary. As these diamonds grew, a microscopic inclusion would sometimes become trapped along the boundary. Using a beam of electrons, the researchers identified 32 inclusions in eight of 30 diamonds they examined. Twenty of those inclusions were the same carbonate-bearing fluids found in the fibrous diamonds.
The finding suggests that while fibrous diamonds and gem-quality diamonds differ in age and price, they share common origins. “We’re coming full circle on the story,” Jablon says. “We can quiet a debate that has been raging in the field for a long time. Going forward, we can generally assume most diamonds crystalize the same way.”

A similar mechanism for creating older, gem-quality diamonds and younger, fibrous diamonds suggests that Earth has maintained diamond-forming conditions for billions of years, Stachel says. Carbonates are carried into Earth’s depths when tectonic plates subduct and sink into the planet’s interior. If ancient diamonds form from carbonates, plate tectonics could have already been churning the planet’s exterior 3.5 billion years ago, he says.

ATLANTA — Grim discoveries in Belize’s aptly named Midnight Terror Cave shed light on a long tradition of child sacrifices in ancient Maya society.

A large portion of 9,566 human bones, bone fragments and teeth found on the cave floor from 2008 to 2010 belonged to individuals no older than 14 years, bioarchaeologist Michael Prout reported April 15 at the annual meeting of the American Association of Physical Anthropologists. Many of the human remains came from 4- to 10-year-olds. Because these bones are so fragmented, it’s difficult to estimate precisely how many individuals lay in the cave.
Prout, of California State University, Los Angeles, and colleagues suspect these children were sacrificed to a rain, water and lightning god that the ancient Maya called Chaac.

Radiocarbon dating of the bones indicates that the Maya deposited one or a few bodies at a time in the cave over about a 1,500-year-period, starting at the dawn of Maya civilization around 3,000 years ago, Prout said. At least 114 bodies were dropped in the deepest, darkest part of the cave, near an underground stream. Youngsters up to age 14 accounted for a minimum of 60 of those bodies. Ancient Maya considered inner cave areas with water sources to be sacred spaces, suggesting bodies were placed there intentionally as offerings to Chaac.

The researchers found no evidence that individuals in the cave had died of natural causes or had been buried.

Until now, an underground cave at Chichén Itzá in southern Mexico contained the only instance of large-scale child sacrifices by the ancient Maya, Prout said. Other researchers have estimated that 51 of at least 101 individuals whose bones lay scattered in Chichén Itzá’s “sacred well” were children or teens.

Researchers have often emphasized that human sacrifices in ancient Central American and Mexican civilizations targeted adults. “Taken together, however, finds at Chichén Itzá and Midnight Terror Cave suggest that about half of all Maya sacrificial victims were children,” Prout said.