It is difficult to figure out the behaviors of an animal that lived thousands—or millions—of years ago when all you have are its fossilized bones, even when there are plenty of them, as there are for the sabertooth cat (Smilodon fatalis). Scientists have to be creative.
Chris Carbon of the Zoological Society of London and others (reporting in the journal Biology Letters) did just this when they asked: Was the sabertooth cat more like the social lion... (below, from the National Zoo)
... or was it like most other modern cats that live solitary lives (below, my friend's cat Motley)?
The scientists used the abundance of bones found at the La Brea tar seeps to estimate the relative abundance of sabertooth cats and other carnivores during the Late Pleistocene. The tar seeps trapped herbivores and the carnivores that came to eat them. Similar modern data came from playback experiments in modern Africa in which the sounds of distressed prey were broadcast to attract carnivores; social carnivores are lured in larger numbers than solitary ones in these experiments.
According to both of these estimates, the numbers “represent competitive, potentially dangerous encounters where multiple predators are lured by dying herbivores. Consequently, in both records predatory mammals and birds far outnumber herbivores,” the scientists explain in their paper.
The playback experiments show that social animals—lions, spotted hyenas and jackals—were the most common, whereas solitary species were rare. In the La Brea record, the “presumably social” dire wolf comprised half of individuals found and the sabertooth a third. Known solitary species were rare, nicely matching the playbacks.
The answer to the question, then, is that sabertooth cats were likely more like lions. Though they did have much bigger teeth.
(Photo Credits: Postdlf via Wikipedia (fossil skeleton from the National Museum of Natural History); Jesse Cohen, National Zoological Park (lion); Sarah Zielinski (Motley))