These animals lived alongside modern species of kangaroos, but specialised on a diet of leaves from trees and shrubs. Their robust skull architecture and shortened faces have been thought to be related to increased masseter muscles used to chew foods. Dental microwear of "P. goliah" supports a browsing diet. Large bicuspids, crenulated dental crowns, and a massive bony jaw present in the fossil evidence of "P. goliah" would have been required to process and digest a substantial amount of leafy fodder. Stable isotopic data suggest its diet consisted of plants using a C4 photosynthetic pathway, typically associated with grasses. In this case, however, chenopod saltbushes found throughout semiarid Australia were considered a more likely source of the C4 signature. [An intensification in aridity during the second half of the Pleistocene propagated the evolutionary progression of "P. goliah" to adapt to an abundance of dry vegetation. Evidence that "P. goliah" was the most widely distributed species among the Pleistocene macropodids throughout the continent shows that this species was adapted to a tougher diet than any other extinct Pleistocene sthenurine. Similar to "Macropus giganteus", "Procoptodon" has molar patterns that indicate they had a similar, grassy, herbivorous diet (as opposed to leaves) and were grazers, but determining specific diets and preference of extinct herbivores is admittedly difficult. Through the study of isotopic composition of "P. goliah" tooth enamel, in addition to biomechanical bone features, dietary clues and feeding behavior have been deduced. The osteological characters furnish evidence of "P. goliah"s ability to handle fibrous vegetables and salt consumption. This, in turn, leads to the belief that the species needed to be close to a water source to deal with salt intake; at the same time, though, some theories are beginning to arise that limb remains indicate the ability to travel distances both to and from water sources.