IOWA CITY, Iowa (AP) -

Researchers say the two mammoth skeletons discovered in southern Iowa are different species of extinct beasts that once roamed the earth.

A University of Iowa-led research team announced Friday that skull fragments and teeth found last month at the site in Oskaloosa are those of a woolly mammoth. The team had already identified a four-foot femur found in April as belonging to a Columbian mammoth.

Sarah Horgen of the university's natural history museum says that finding two species in one spot is a first in Iowa and raises many questions, such as whether they lived together and were present at the same time.

Researchers say Columbian mammoths were larger than woolly mammoths and had long spiraled tusks. Both died out when the Ice Age ended about 11,000 years ago.