Being omnivorous would have allowed them to niche-partition with the  hypercarnivorous sparassodonts and terror birds that it lived alongside. Bite marks attributable to Chapalmalania have been found on a glyptodont carcass and have been interpreted as scavenging behavior, suggesting that Chapalmalania also fed on carrion of large mammals such as glyptodonts on at least some occasions, the blunt cusps of its molars well designed to grind down tough foods.
Having an omnivorous diet would have enabled them to coexist with the hypercarnivorous sparassodonts and terror birds that they shared their habitat with. The presence of Chapalmalania's bite marks on a glyptodont carcass has been interpreted as evidence of scavenging behavior, implying that Chapalmalania also consumed carrion from large mammals like glyptodonts on some occasions, thanks to the blunt cusps of its molars.