Body Shape Analysis in Reticulated Giraffe, Okapi, and Black Rhinoceros Using Three-Dimensional Laser Measurements

Abstract

Health management in captive animals is difficult for various unknown reasons presumably related to physiological functions, disease, and diet. Generally, abnormal conditions are diagnosed based on body weight; however, zoos lack appropriate scales for megafauna. Body shape evaluation is often used to evaluate the nutritional status of breeding animals; however, this is inaccurate for zoo animals because of inter-observer variability, especially in megafauna. Previously, three-dimensional laser measurements were used to analyse body shape of reticulated giraffe, but further studies are required to examine its effectiveness in more individuals, and other species. Here, we applied this method to seven reticulated giraffe (Giraffa reticulata), five okapi (Okapia johnstoni), and three black rhinoceros (Diceros bicornis) individuals for which cross-sectional area, width, and height in transverse section were determined. Relative change rates of each variable in relation to measurements at the axillary region revealed changes in body shape for each individual. Further, scatter plots and corresponding fitted curves and correlation coefficients showed a correlation between body length and approximate volume. The accuracy of three-dimensional laser measurements was demonstrated in three animal species, whereby we propose its use as an alternative method to evaluate body shape in megafauna without the inter-observer variability. In addition, this handheld device may be applied for various zoos without the scale for megafauna.