Foot areas, ground reaction forces and pressures beneath the feet of kangaroos, wallabies and rat-kangaroos (Marsupialia : Macropodoidea)

Foot areas of a wide range of kangaroos, wallabies and rat-kangaroos were m easured from fresh material and museum specimens. The areas of the plantar pads scaled according to the predictions of geometric similarity. The termi nal claw areas of digits IV and V scaled with a lower than predicted expone nt, reflecting functional demands of different species. The pressure that t hese marsupials exert on the ground during quiet standing is proportional t o (body weight)(0 35), and is considerably lower than those exerted by ungu lates. Hopping kangaroos exert pressures proportional to (body weight)(0.37 ). The pressures exerted by medium and large macropods are comparable to th ose of galloping ungulates. The findings support the commonly held belief t hat introduced grazing animals may cause greater mechanical disruption of t he soil surface, leading to increased rates of soil erosion, than Australia 's indigenous grazing fauna.