Complex sentence: Another animal that smilodon out competed was the marsupial lion it also lived in south america and had sabre teeth the competition for prey led them into rivalry and eventually into the extinction of the marsupial lion.
Split into simpler sentences: Another animal that smilodon out competed was the marsupial lion, which also lived in South America and had sabre teeth as well. The competition for prey led them into rivalry and eventually led to the extinction of the marsupial lion.