PARRA, Laura G.*; HYDE, Martha L.; West Texas A&M Univ., Canyon; West Texas A&M Univ., Canyon: Characterization of Bipedal Locomotion While Feeding in Kangaroo rats in the Natural Habitat

Kangaroo rats of the species Dipodomys ordii were filmed in their natural habitat at Alibates Quarry, Texas using an infrared camera. A 100 cm x 50cm x 50cm frame was built with bicycle reflectors set at 10 cm intervals on the backbone of the frame to allow accurate measurement of distances traveled on the infrared film. The rats were enticed into the frame by placing seeds on either side of the frame. Linear displacement, speeds and accelerations of the toe, ankle, knee, body, and center of gravity were all measured. Angles of projection, jump heights, stride times, and stride lengths were compared to data collected from other studies, which used �natural� substrates that were made to mimic the caliche substrate in their native habitat. The average velocity of the rats studied in the laboratory was 2.00 m/sec when moving over a bare platform (hard metal surface) and thick foam, 0.022 m/sec on thin foam, and 0.275 m/sec in their natural habitat. The average angle of projection varied from 83- 86&deg on bear metal and foam substrates in the laboratory. Locomotion on natural substrates filmed in the laboratory had similar measurements to those filmed in their natural habitat (53- 59&deg, 60&deg, respectively). Jump height ranged from 1.5- 2.9 cm on natural substrates in the laboratory, 7.8 cm on a bare platform, 8.8 cm on thick foam,10.5 cm on thin foam, and 2.2 cm in their natural habitat. The difference between the laboratory results and the natural habitat results might be due to motivation. The qualities of the natural habitats may also largely influence locomotor parameters in bipedal kangaroo rats. The study was partially funded by West Texas A&M University and the Ronald E. McNair post-baccalaureate achievement program.