Woolly mammoths (Mammuthus primigenius) roamed the planet for more than a million years, ranging from Europe to Asia to North America. Nearly all of these giants vanished from Siberia by about 10,000 years ago.

The Columbian mammoth (Mammuthus columbi) preferred the more temperate regions of southern and central North America. The Columbians were much larger than woollies, with Columbian males reaching one-and-a-half to two times that of woolly males.

Researchers have discovered the mitochondrial genome of the Columbian mammoth was nearly indiscernible from that of its northern woolly counterparts.   Woolly mammoth may have interbred with elephants.
 
Mammoth evolutionary puzzle: Unpicky woollies were happy to interbreed - ScienceCodex