Meeting Abstract
Giraffes (Giraffa camelopardalis) are ruminant artiodactyls whose large body mass combined with long, gracile limb and neck proportions render them highly specialized in comparison to sister taxa. Previous studies have been confined to describing kinematics from a small number of trials, usually with single individuals. Our previous work has described the kinematics and ground reaction forces from walking giraffes in a zoological park. Here we quantify the kinematics from fast-moving, free-ranging giraffes. We measured kinematic variables (including speed, duty factor, stride length and frequency) from a sample of 35 free-ranging giraffes, from three field locations in the Free State, South Africa. We used an unmanned aerial vehicle (drone) to gather video footage of running giraffes, over a range of body sizes and stages of ontogeny. Each video frame was calibrated using leg length as a known dimension. Leg length was measured using a combination of close range photography, and GPS calibrated ground measurements. Running speeds ranged from 2.8 – 11 m/s. Across the studied speed range, the predominant running gait was a 4-beat rotary gallop with no suspension phase, although gathered suspension was noted in some juvenile individuals. Stride frequency ranged from 1 – 1.4 Hz, and stride length 2.9 – 8.3 m. When compared with other large ungulates (eg. the horse), this pattern illustrates a tendency for conservative stride frequencies in giraffes, where faster speeds are instead achieved by marked increases in stride length.
