Abnormal neck bones suggest inbreeding spelled extinction of woolly mammoths

Thanks to Hollywood, woolly mammoths are arguably the most endearing creatures from the last ice age. Researchers have been searching for clues to solve the mystery of their extinction and the answers may lie in an ancient mammoth neck rib.

The woolly mammoth is one of the most well-known species of mammoth. These gentle giants roamed the northern parts of Asia, Europe and North America during the Pleistocene era. Woolly mammoths were also hunted by early humans either for meat or for raw materials. Mammoth tusks and bones were used for making a variety of things such as weapons, tools and art. 10,000 years ago, the woolly mammoth died out and scientists have been looking for answers to unlock the mystery of its disappearance.

Woolly mammoths died out during the Quaternary extinction event. While experts are quick to point out that these ancient elephants may have died out either through over hunting or because of climate change, scientists are still trying to piece together the entire picture. The latest piece of the puzzle was found by studying ancient mammoth neck ribs.

"It had aroused our curiosity to find two cervical vertebrae, with large articulation facets for ribs, in the mammoth samples recently dredged from the North Sea," said Jelle Reumer, a paleontologist from the Natural History Museum of Rotterdam. "We knew these were just about the last mammoths living there, so we suspected something was happening. Our work now shows that there was indeed a problem in this population." Reumer is also one of the co-authors of the study published in the online journal PeerJ.

The study was conducted by researchers from the Naturalis Biodiversity Center in Leiden and the Museum of Natural History in Rotterdam. Their findings show that the unusual cervical rib may be a symptom of a larger problem affecting the woolly mammoths. The occurrence of cervical ribs can be caused by problems during the embryonic development of a mammal or genetic abnormalities. This type of disorder can also be seen in modern mammals

Since cervical ribs are considered a birth defect, the presence on these ribs on woolly mammoth remains may have been caused by inbreeding due to diminished populations. Inbreeding decreases genetic diversity and may cause genetic abnormalities that can weaken populations of woolly mammoths. Coupled with environmental factors, disease and a lack of food, these abnormalities may have pushed the woolly mammoth over the edge and into extinction.