Comportamento postural e locomotor ao escalar de sete espécies marsupiais (Didelphimorphia) da Mata Atlântica

Abstract

The stratification of didelphids on the arboreal strata seem to be related to their body size, anatomical differences and resources partitioning. Researches on their arboreal ability are still lacking and they could reveal specifics behaviors. ln this study was investigated climbing gait on vertical supports of seven species: Caluromys philander (canopy arboreal), Gracilinanus microtarsus, Micoureus travassossi, Marmosops incanus (understory arboreal), Didelphis aurita, Philander frenatus (semi-terrestrials) e Metachirus nudicaudatus (terrestrial). It was expected distinct locomotion strategies related to the arboreal stratum utilized and to the reached speed. The animais were trapped in Atlantic forest areas, RJ, and removed. At the laboratory, locomotory tests were applied with vertically nylon ropes with three diameters. These tests were filmed and the images digitized for climbing analysis. Gait diagrams and a frame-by-frame analysis were made to select the individual with the fast gait sequence and a typical climbing posture of its species. To compare differences according to speeds, a gait sequence from two individuais were selected (one in the minimum other in the maximum speed) of each species, on the three ropes. Locomotion graph was used to classify the gait sequences. The arboreal species moved their limbs like a trot, been different from the other species and maintained their body far off the rope. M. incanus and P. frenatus altered their gait sequences with the speed reduction, and relied on three limbs. The tail was not useful for climbing. Thus, arboreal species had more stability and agility climbing, for been able to reach high speed with two support limbs and maintain their body far off the rope.