Morphometry and ageing of captive male asian elephants (Elephas maximus)

Abstract

The collection of morphometric details from elephants of different age groups would enhance our biological understanding and management of this valuable species.. A total of fifty two clinically healthy captive male Asian elephants, varying in age, under excellent management, maintained by 'Guruvayoor Devaswom Board' were utilized for predicting body weight and height from body measurements as well as determination of age from physical features. For prediction equations several morphometric parameters were measured. All possible linear regressions of weight on one, two, three and four body measurements were calculated. The equations having highest coefficient determination value (R2) with least standard error of estimation was taken for predicting body weight and height in elephants. The data were also divided into age groups (Group I (Young ones; 0-20 years), Group 11 (Sub adults; 21-30 years), Group III (Adults; 31-40 years), and Group IV (0 Id adults; 41-70 years)) and all possible linear regressions were calculated for each group. The best prediction of body weight (kg) for all age groups (G I to G IV) was obtained based on two parameters; the chest girth (cm) and right forefoot circumference (cm). Single and also the combination of various parameters were used for the prediction' of body weight in different age groups. An equation to predict the height at the shoulders (cm) from right forefoot circumference (cm) for various age groups of elephants was also derived. Various parameters were correlated with age of the elephants and average values of these parameters were salculated for age approximation. The data were again divided into various age groups (Group A (Young ones; 0-20 years), Group B (Adults; 21-40 years), and Group C (Old adults; 41- 70 years)) and comparison of parameters between two age groups was done. The

parameters such as depigmentation on the trunk, hair distribution, hollow on the temple region, width of the ear, circumference of tusk base and middle, and height at the shoulders had high correlation as well as significant difference in various age group comparisons. So, these parameters could be useful for age estimation in male elephants with more precision.