Glide angle in the genus Petaurus and a review of gliding in mammals

The gliding angle of the Mahogany Glider Petaurus gracilis and the Sugar Gl ider Petaurus breviceps was determined from field studies by measuring the height of launch and landing of glides and the distance travelled. This sho wed no significant difference between these two species in glide ratio, whi ch averaged 1.91 and 1.82 m distance per 1 m loss in altitude, respectively , nor in glide angle which averaged 28.26 degrees and 29.69 degrees for the Mahogany Glider and Sugar Glider, respectively. Significant differences we re found between them for height of launch (19.75 and 11.96 m, respectively ), height of landing (4.48 and 1.95 m, respectively), diameter at breast he ight of landing tree (44.12 and 23.22 cm, respectively), and glide distance (29.71 and 20.42 m, respectively). An examination of the ratio of interorb ital width to maximum skull width of gliding and nongliding possums was mea sured from museum skulls to examine whether gliders have eyes wider apart, to allow triangulation of distance in preparation for gliding. Gliding poss ums showed a trend toward having a larger interorbital width than nonglidin g possums, although there appear to be several factors acting on the intero rbital width. Museum study skins of all gliding marsupials were measured to determine the relationship between patagium surface area and body mass whi ch showed a clear relationship (r(2) = 0.9688). A comparison of gliding beh aviour, patagium, development of limbs, tail morphology and mass was also m ade between gliding marsupials and other gliding mammals.