Meeting Abstract
One of the factors impacting the diversity of locomotor modes in animals is the habitat in which movements are performed. Environments like water and land impose different physical demands and, as a result, many species that operate in both environments use a distinct mode of locomotion in each; for example, swimming in water versus walking on land. However, many species that move between land and water may continue to use a terrestrial mode of locomotion in aquatic environments. If animals are not entirely submerged, such behaviors are termed wading, and are present in a variety of taxa including amphibians, reptiles, mammals, and birds. As animals move through water of increasing depth, species with long legs may be able to lift their feet above the water surface to reduce drag that could slow their performance. However, there may also be a critical depth, above which it becomes awkward to raise the foot above the surface, and kinematics again resemble terrestrial patterns of movement. To test these predictions, head, body, and limb kinematics of the long-legged Chilean flamingo (Phoenicopterus chilensis) were measured as birds walked through increasing depths of water in a zoo enclosure. A variety of kinematic changes occurred across environmental conditions. As flamingos moved through deeper water, they showed a combination of slower movements with mass concentrated closer to the body that may help to increase stability as hindlimb angular excursions became more exaggerated. Although a critical depth at which wading kinematics began to resemble those used in terrestrial habitats was not identified over the range of depths tested, our results show that wading birds can implement a range of kinematic strategies to enable successful movement through different water depths.
