Evolution photo

A complete mammoth skull has been excavated from a stream bank on Santa Rosa Island, California, the National Park Service announced Wednesday.

“It appears to have been on the Channel Islands at the nearly same time as humans,” paleontologist Justin Wilkins said in a statement. The U.S. Geological Survey has dated charcoal samples found near the fossil to 13,000 years–the same age as Arlington Springs Man, the oldest human remains found in North America (and fellow tenant of Santa Rosa Island, which is located within Channel Islands National Park).

The skull is larger than those of pygmy mammoths, but smaller than a typical Columbian mammoth skull. The fossil may have been a young Columbian mammoth. If so, this might indicate that the species migrated to the Channel Islands twice–once about 150,000 years ago, allowing its descendants time to evolve into pygmy mammoths, and a second time between 10 and 30,000 years ago. It’s less likely but possible that the mammoth represents a transitional species between Columbian mammoths and pygmy mammoths.

The scientists expect to shed some light on exactly when the mammoth died and which species it belonged to by studying its fossilized teeth.