SIZE DEPENDENCE IN PROSIMIAN LOCOMOTION AND ITS IMPLICATIONS FOR THE DISTRIBUTION OF BODY-MASS

The mechanical requirements for arboreal life are reviewed and the con straints which these requirements impose on the body of a prosimian ar e defined. The mechanical necessities can be fulfilled only by animals which possess the appropriate morphological characters. It is incorre ct to refer to these morphological traits directly as 'adaptations'. I nstead their a priori existence must be considered as the precondition for the acquisition of a certain life-style. Once such a life-style h as been acquired, a strong selective pressure acts towards a further r efinement of such 'adaptations' or 'pre-adaptations', Postcranial morp hology must be seen in a context of following natural laws and is stri ctly related to the mechanics of posture and locomotion. The traits em phasised and explained here are body proportions - specifically the re lative lengths of body segments and the distribution of(muscle) mass o n these segments.