Meeting Abstract

P2.50  Thursday, Jan. 5  A new 3D system for measuring burrowing biomechanics MOORE, A.L.*; BARNES, C.J.; LEE, D.V.; Univ. of Nevada, Las Vegas; Univ. of Nevada, Las Vegas; Univ. of Nevada, Las Vegas moorea3@unlv.nevada.edu

Subterranean digging behaviors provide opportunities for protection, access to prey, and predator avoidance to a diverse array of vertebrates, yet studies of the biomechanics of burrowing have been limited by the technical challenges of measuring kinetics and kinematics of animals moving within a substrate. Previous studies of burrowing typically use 2D X-ray video and 1D force measurements, however, empirical observations show that burrowing mechanics are not restricted to a single axis or plane. Here we present a new system for simultaneously measuring 3D kinematics and kinetics of burrowing animals by combining 3D X-ray motion analysis with an innovative ‘tunnel-tube’ for measuring 3D burrowing reaction force together with outward pressure on the tunnel walls. The tunnel-tube is a rigid acrylic cylinder supported at each end by six-axis load cells for measuring net reaction forces and the lengthwise center of pressure during burrowing. To measure the outward pressure on the walls of the tunnel, a nitrogen-pressurized inner-tube separates the rigid outer wall of the tunnel-tube from the substrate filled interior. A pressure transducer in this nitrogen-filled space records the outward pressure due to soil compaction against the rubber inner-tube. Separate vertical and horizontal forces during burrowing strokes may also be measured independently using flex-sensitive resistors arranged in concentric bands along the length of the inner-tube. Measured simultaneously, 3D X-ray kinematics 3D reaction force and dynamic pressure data will provide a more complete view of burrowing biomechanics in a diversity of vertebrates.