The creatures lacked even vestigial wings; they looked like walking bags of feathers with a small head perched on top. The moa were the dominant large herbivores in New Zealand, which had no native mammals, save for bats.
Over the next century or so, the moa disappeared. Their very existence was unknown until the 19th century, when excavations of Maori shell heaps revealed oven-charred skeletons, gizzard stones and eggshells.
Scientists have long assumed that humans played a role in the moa’s obliteration, but that became a subject of debate. Some researchers believed that the bird was already on the way out when humans arrived, thanks to factors like climate change, volcanic eruptions and disease.
But now scientists have turned to a relatively new DNA examination technique called microsatellite analysis, also used in forensics and paternity suits. The inescapable conclusion, they report in Proceedings of the National Academy of Sciences, is that humans were the sole culprits.
Morten Erik Allentoft, a researcher at the University of Copenhagen, and colleagues analyzed DNA from 281 moas collected from museums and new excavations, and estimated the age of those specimens using radiocarbon dating. They found that in the millenniums before humans arrived in New Zealand, the moa displayed none of the genetic bottlenecking indicative of a declining population.
The South Island giant moa even appeared to be on the rise when people arrived. “Nothing at all suggests a decline in the 5,000 years before the moa’s extinction,” Dr. Allentoft said. “Then humans arrive and it happens very fast: This big, healthy population hits the wall and disappears.”
Even today, though, some people hold out hope that moas survive somewhere. Some hotels offer to take tourists into the mountains to look for them, Dr. Allentoft said, adding, “These birds are too big to walk around undiscovered for that many years.” RACHEL NUWER
Keywords clouds text link
Dịch vụ seo, Dịch vụ seo nhanh , Thiết kế website , máy sấy thịt bò mỹ thành lập doanh nghiệp
Visunhome, gương trang trí nội thất cửa kính cường lực Vinhomes Grand Park lắp camera Song Phát thiết kế nhà thegioinhaxuong.net/
|aviatorsgame.com ban nhạc||confirmationbiased.com|
|mariankihogo.com ốp lưng||Giường ngủ triệu gia|
mặt nạ mặt nạ ngủ Mặt nạ môi mặt nạ bùn mặt nạ kem mặt nạ bột mặt nạ tẩy tế bào chết mặt nạ đất sét mặt nạ giấy mặt nạ dưỡng mặt nạ đắp mặt mặt nạ trị mụn
mặt nạ tế bào gốc mặt nạ trị nám tem chống giả
© 2020 US News. All Rights Reserved.