Saber-toothed cats are famed for their gnarly grins, but it seems that behaviourally, they were pretty unique too. Just like today’s lions, it appears they went against the big cat gradient, forming social circles and even tending to the sick.

Over 10,000 years ago, during the Late Pleistocene, a type of saber-toothed cat called Smilodon roamed the Earth. It’s often referred to as the saber-toothed tiger, however this is misleading as the cat was not closely related to tigers.

Smilodon’s canines measured an impressive 28 centimeters (11 inches) in length. The animals were about a foot (0.3 meters) shorter than today’s lions, but chunkier, as they were twice as heavy.

By examining the skulls of fossilized Smilodon cats found in the La Brea tar pits – an area where sticky tar has seeped out of the ground for many thousands of years, trapping animals in the process – researchers worked out that the felines were likely more social than thought, as it appears injured cats were kept alive by healthy ones sharing their dinner.

The team looked at the patterns of damage on the teeth of 135 cats with healthy jaws, and 21 that had sustained jaw injuries. They found that the healthy cats ate a combination of flesh and bone, crunching up the entirety of their prey as lions do. In contrast, injured saber-tooths appeared to only eat soft flesh as the damage on their teeth was more similar to that of today’s cheetahs, which tend to avoid chowing down on bone.

Since the injured cats would’ve had a hard time taking down their prey, which was bigger than the prey of today’s big cats, the researchers concluded that they were feeding on the soft flesh of animals killed by their healthy counterparts.

“The fact that they’re eating food that really shouldn’t be available to them unless they’re being provided for, and that they’re living with these injuries for prolonged periods of time suggests they’re being provisioned food by other cats,” lead author Larisa DeSantis, who presented the findings at the Geological Society of America Annual Meeting, said in a statement.

As many of the saber-tooth cat fossils show signs of healed wounds, it seems the cats likely formed social groups, as their injuries would have been lethal without support from others. The sociability of saber-tooths is still up for debate, but more and more evidence points to social interaction.

“There is a lot of evidence that Smilodon was a social and gregarious animal, which implies that they hunted together and fed at group kills,” explained study co-author Christopher Shaw. “This study adds another provocative aspect to the sociability within this species and, for the first time, addresses new evidence regarding food options and feeding behaviors for injured members of the social group.”