Anthropologists in Mexico have unearthed ancient pits used to trap mammoths. The remains of 14 woolly mammoths were found inside the 15,000-year-old, human-dug pits.

"[The discovery] represents a watershed, a touchstone on what we imagined until now was the interaction of hunter-gatherer bands with these enormous herbivores," Pedro Francisco Sánchez Nava, national coordinator of archeology at Mexico's National Institute of Anthropology and History, said in a news release.

Previously, anthropologists and archaeologists surmised that mammoth hunting mostly happened on accident, or serendipitously. Mammoths, many researchers assumed, were only attacked by humans when hunters happened upon the animals in a compromised position -- a mammoth stuck in a swamp, for example.

The latest discovery suggests, to the contrary, that some of the earliest settlers of the Basin of Mexico used the environment and social organization to systematically hunt woolly mammoths.

The land where the ancient pits and trapped mammoths were found is located in the neighborhood of Tultepec, a few miles north of Mexico City. Researchers spent 10 months excavating a total 824 mammoth bones at the dig site, dubbed Tultepec II.

The dig site was slated to become a garbage dump, but the discovery put the plans on hold. Some 15,000 years ago, the land was newly exposed -- lake beds that had dried as growing ice caps caused sea levels to decline.

Layers of ash from the eruption of Popocatepetl, 14,700 years ago, were found above and between layers of mammoth bones, which suggests the pits were in use for at least 500 years.

According to Salvador Pulido, director of archaeological excavations at INAH, the Tultepec II discovery could just be the "the tip of the iceberg." Radar surveys of surrounding mammoth grave sites could reveal the presence of similar traps.

"Here we had the opportunity to have profiles of tens of meters, that's why we warned that we were literally in prehistoric traps," Pulido said. "We could argue that in other archaeological salvages we have been in a similar context, but the limits of the excavations only let us see horizontal strata."

Melting Arctic ice accelerates spread of deadly virus in marine mammals
(UPI) Nov 7, 2019 - New research suggests the loss of sea ice in the Arctic is aiding the spread of a deadly virus among marine mammals.

In 2002, the phocine distemper virus, or PDV, infected and killed thousands of harbor seals in the North Atlantic. Two years later, scientists identified the virus in northern sea otters in Alaska.

The latest research, a 15-year study published Thursday in the journal Scientific Reports, suggests shifting sea ice dynamics in the region enabled increased contact between Arctic and sub-Arctic seals, allowing the virus to spread from the Atlantic to the Pacific.

"The loss of sea ice is leading marine wildlife to seek and forage in new habitats and removing that physical barrier, allowing for new pathways for them to move," study co-author Tracey Goldstein, associate director of the One Health Institute at the University of California-Davis School of Veterinary Medicine, said in a news release. "As animals move and come in contact with other species, they carry opportunities to introduce and transmit new infectious disease, with potentially devastating impacts."

Between 2001 and 2016, scientists tested dozens of marine mammals, including seals, northern fur seals, Steller sea lions and northern sea otters, for the presence of phocine distemper virus.

Researchers used satellite images to monitor the presence of open water routes from the North Atlantic to North Pacific oceans. Peaks in infection rates in 2003 and 2009 corresponded with significant reductions in the Arctic sea ice extent.

"As sea ice continues its melting trend, the opportunities for this virus and other pathogens to cross between North Atlantic and North Pacific marine mammals may become more common," said Elizabeth VanWormer, the study's first author and a former UC Davis researcher, now an assistant professor at the University of Nebraska, Lincoln. "This study highlights the need to understand PDV transmission and the potential for outbreaks in sensitive species within this rapidly changing environment."

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