The woolly mammoth, one of the prehistoric animals that looked like present day elephants, suffered from birth defects in its last years before extinction. The changing climatic conditions associated with inbreeding was the main factor that led to extinction of woolly mammoth, according to a new study.
The study was conducted by researchers from Rotterdam Museum of Natural History and the Naturalis Biodiversity Center in Leiden. They believe that such factors add on to reproductive related stress.
While studying the fossil remains of 12,000-year-old mammoth that was discovered near the North Sea, researchers found that woolly mammoths possessed a cervical rib or neck rib.
Cervical ribs are located in the neck on the cervical vertebrae and this change is the result of environmental stress and genetic mutation during pregnancy, which in turn is associated with still births and abnormalities.
They have also found that the formation of cervical ribs were more common in North Sea woolly mammoths than in today's elephants and were astonished to find such numbers of cervical ribs among them.
"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. 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," said Jelle Reumer, an author of the study and a paleontologist at the Natural History Museum of Rotterdam and Utrecht University, in a statement.
"The high incidence and large size of the cervical ribs in woolly mammoths indicates a strong vulnerability, given the association of cervical ribs with diseases and congenital abnormalities in mammals. The vulnerable condition may well have contributed to the eventual extinction of the woolly mammoths." said a researcher.
The team of researchers thus conclude that such developmental abnormalities resulted in the extinction of the woolly mammoths.