Primates have evolved a wide range of locomotor behaviours to enable them to negotiate a three dimensional arboreal environment. Included in the primates are the lemurs, which have gained a reputation as specialist leapers with the sifaka (P. verreauxi) known for incredible saltatory displays.It is therefore necessary to have knowledge of this animals locomotor repetoire, substrate use, ranging and activity patterns in order to gain a greater understanding of sifaka ecology. The sifaka also inhabits a dry deciduous forest located in south western Madagascar which is characterized by a long dry season and short rainy season. This thesis begins with an investigation into the locomotion of P. verreauxi within Kirindy Mitea National Park. It was shown that leaping made up the largest proportion of the sifakas' locomotor repetoire and that vertical supports were the most utilized, supporting the idea that sifakas are vertical clingers and leapers. Seasonal changes in behaviour were also displayed with levels of traveling behaviour increasing and resting behaviour decreasing during the short rainy season. These findings added weight to the growing body of evidence that lemurs conserve energy during periods of food scarcity in order to survive during the long dry season.These results were further supported by a ranging study, which used hand held GPS devices to measure home ranges and daily path lengths. It was discovered that the sifakas' daily path lengths are much lower than that of both Old and New World monkeys. These path lengths also vary seasonally with decreased daily ranging during the dry season. A newer method of data collection was also investigated with the use of accelerometer data loggers being used in an attempt to monitor locomotion remotely. Although a captive study displayed that different locomotor modes can be distinguished from acceleration data, a field experiment using a very similar methodology failed to yield any useable data.The results suggest that P. verreauxi adapts its locomotor behaviour seasonally in order to cope with extended periods of food scarcity. helping add weight to the idea made by previous researchers that lemurs living in highly seasonal environments are adapted for conserving energy to deal with a harsh environment.