BIOMECHANICS IN BEHAVIOUR. Introduction. Behavioural biomechanics in organismal biology. Behaviour and the mechanical properties of the environment, certain animal structures and tools. Conclusions. BIOMECHANICS AND BEHAVIOUR: ANALYZING THE MECHANISTIC BASIS OF MOVEMENT FROM AN EVOLUTIONARY PERSPECTIVE. Introduction. Phylogeny and the study of biomechanics and behavior. Two case studies. Discussion and prospectus. INTERMITTENT LOCOMOTOR BEHAVIOUR ALTERS TOTAL WORK. Introduction. Predictions from biomechanics and energetics based on laboratory studies of steady-state locomotor behavior. Predictions based on laboratory studies on non-steady-state locomotor behavior. Testing laboratory-based predictions from mechanics and energetics by measuring locomotor behavior in the field. Generality of the consequences of intermittent locomotor behavior in other ectotherms. Conclusion. WALKING AND RUNNING STRATEGIES FOR HUMANS AND OTHER MAMMALS. Introduction. Gaits and speeds. Routes. Taking risks. FISH SWIMMING BEHAVIOUR: PREDICTIONS FROM PHYSICAL PRINCIPLES. Introduction. Gaits as basic swimming behaviours. Simple swimming behaviours. Complex behaviours. From individual behaviours to whole organisms. Conclusions and future studies. THE BIOMECHANICS OF INTERMITTENT SWIMMING BEHAVIOURS IN AQUATIC VERTEBRATES. Introduction. Burst-and-coast swimming. Energy efficient swimming strategy in negatively buoyant fish. Porpoising. Flying fish. Conclusion. Notation. BIRD MIGRATION PERFORMANCE ON THE BASIS OF FLIGHT MECHANICS AND TRIGONOMETRY. Introduction. Gliding and flapping birds. Speed of migration. Range and fuel load. The triangle of velocities. Migration by vector summation. Routes on a globe. Final remark. Appendix: List of symbols. AERODYNAMICS AND BEHAVIOUR OF MOULT AND TAKE-OFF IN BIRDS. Introduction. Avian moult. Take-off in birds. Moult and take-off. Discussion. THE PHYSICS OF CHEMORECEPTION REVISITED: HOW THE ENVIRONMENT INFLUENCES CHEMICALLY MEDIATED BEHAVIOUR. Introduction.