the region may have supported a dense closed forest during the Late Pleistocene. It is possible that the region alternated between dry open savannah and closed wet forest throughout the climate change of the Late Pleistocene.Smilodon may have occasionally preyed upon Glyptotherium, based on a skull from one Glyptotherium texanum individual recovered from Pleistocene deposits in Arizona bearing the distinctive elliptical puncture marks that best match those of the machairodont cat, indicating that the predator successfully bit into the skull through the armored cephalic shield. The Glyptotherium in question was a juvenile, with a still-developing head shield, making it far more vulnerable to the cat's attack. In 2017, a right ulna of an adult Glyptotherium that had been collected from Late Pleistocene-Early Holocene strata in Rio Grande do Norte State, Brazil was described that bore several gnawing traces from a new ichnospecies of Machichnus, M. fatimae, that may have been caused by a juvenile of the canid species Protocyon troglodytes or an adult individual of Cerdocyon thous. Relationship with humans The first report of possible human consumption or interaction with Glyptotherium or its fossils came in 1958, where several osteoderms that were possibly consumed by humans were described from the Clovis site in Lewisville, Texas, though there is little evidence to back up this assessment. In 2022, a host of fossils of Glyptotherium cylindricum including skulls were described that had been collected from several sites in Falcon, northern Venezuela that dated to the Late Pleistocene-Early Holocene. These discoveries were notable not only because they preserved skulls, but four of them exhibited breakages in the fronto-parietal region, a pattern in all of the skulls. Visual and CT evidence indicates that these were likely caused by a mechanical effect by direct percussion, most likely a blow with a stone chopper or club, which caused the bones in the region to fragment into the soft internal tissues of the skull. Despite the fact that the skulls were complete and showed no signs of taphonomic distortion or transport, they often lacked their jaws. The jaws may have been removed for "hunters" to access and consumed masticatory muscles and tongue. The coexistence of early hunter-gatherer humans and glyptodonts in South America was first hypothesized in 1881 based on fossil discoveries from the Argentine Pampas, and many fossil discoveries from the Late Pleistocene to Early Holocene have been unearthed since that exhibit human predation on glyptodonts.