Columbian mammoth
A 2011 genetic study showed that two examined specimens of the Columbian mammoth were grouped within a subclade of woolly mammoths. This suggests that the two populations interbred and produced fertile offspring. A North American type formerly referred to as "M. jeffersonii" may be a hybrid between the two species. A 2015 study suggested that the animals in the range where "M. columbi" and "M. primigenius" overlapped formed a metapopulation of hybrids with varying morphology. It suggested that Eurasian "M. primigenius" had a similar relationship with "M. trogontherii" in areas where their range overlapped.