HUTCHINSON, J.R.*; FAMINI, D.; KRAM, R.; LAIR, R.: Do elephants run?
We have recorded Asian elephants moving 50% faster than any previous documented report. Our kinematic data range from 0.5 m/sec to 6.1 m/sec for 16 individuals spanning ~500 – 5000kg body mass. Even at the fastest speeds, these elephants did not change their footfall pattern as they increased speed; they used a lateral sequence walk with diagonal support. At least one foot was in contact with the ground at all times, and no discrete change of kinematic parameters suggested a gait change. Yet remarkably, these elephants reached Froude numbers exceeding 3.0. Most animals switch to running gaits at Froude numbers ~0.5 (Froude number is a dimensionless speed = v2/(g * L) where v is velocity, g is gravity and L is leg length). Duty factor (the fraction of the stride that a given foot is on the ground) was as low as 0.37. Most animals switch to running when duty factor is <0.5. In addition, in some faster trials the motion of the hip and/or shoulder joint followed a concave arc during stance, as in running, rather than a convex arc, as in walking. These data hint that elephants may use running kinetics at faster speeds while maintaining walking limb kinematics at all speeds. Supported by a JEB Travelling Fellowship and the TECC.
