Complex sentence: Like extinct sabertooths, it has one of the largest canines of any marsupial relative to body size and was proposed as a a living model to test hypotheses about hunting strategies of the extinct predators.
Split into simpler sentences: Like extinct sabertooths, it has one of the largest canines of any marsupial relative to body size. It may serve as a living model to test hypotheses about hunting strategies of the extinct predators.