The anatomical structure of their locomotor system suggests quadrupedal locomotion, but they were also capable of changing to a bipedal stance.

The structure of the auditory system shows that Glossotherium could perceive frequencies in infrasound and probably produce them with the help of its voluminous nasal cavity.

Glossotherium belongs to the Mylodontidae, in which it is further subcategorized into the Mylodontinae, characterized both by the loss of the entepicondylar foramen of the distal humerus and anteriorly broad snouts.

The latter three have frequently been confused for each other in scientific literature,[3] though it is likely Paramylodon and Glossotherium share a more recent common ancestor than with any other mylodontid.

[5][6][7] Pleistocene records indicate that it was widely distributed between 20°S and 40°S, with a range spanning across Argentina, Brazil, Bolivia, Chile, Colombia, Ecuador, Peru, Uruguay, Venezuela and Paraguay.

Due to its size and strength, Glossotherium would have had few natural enemies apart from the South American short-faced bear Arctotherium and sabre-toothed cats such as Smilodon.

However, based on dental evidence, Glossotherium was likely more suited to grazing, though it was also probably less efficient at ingesting grasses since its dental apparatus was more suited to shearing, which would have been too ineffective at processing plant materials down to an ingestible size to obtain adequate nutritive value.

[3] Evidence from Santa Elina suggests that the niche breadth of G. phoenesis decreased from the Last Glacial Maximum onward.

[11] Glossotherium had large ear ossicles, similar to those in elephants, which imply the loss of hearing acuity of higher frequencies, further implying an advantage for sensing low frequency sounds, infrasound, or bone-conducting seismic waves.

This indicates evidence of an underground lifestyle since loss of high frequency hearing is common to fossorial mammals.