Estimation of body weight in Indian elephants (Elephas maximus indicus)

Abstract

Thirty-nine adult Indian elephants (Elephas maximus indicus) of both sexes and various ages and weights, belonging to the Forest Department of the Government of Kerala (India), Temple Devaswoms, Gemini Circus and other private agencies, were used to derive formulae to predict body weight and height from body measurements. Several models were fitted separately for males and females and also for adults irrespective of sex. The best prediction of body weight (W) in kg was obtained for adults irrespective of sex by using two parameters, the body length (L) in cm from the base of the forehead to the base of the tail, and the chest girth (G) in the formula W = -1010 + 0.036 (L x G). No single parameter gave as accurate a prediction of the body weight, and the inclusion of height as a third parameter did not improve the prediction. No significant improvement in the accuracy of prediction resulted from the use of different formulae for males and females. An equation to predict the height at the shoulders (H) in cm from the right forefoot circumference (C) in cm in adult elephants irrespective of sex was also derived. This was H = -1.60 + 1.99 C.

How Big Is It Really? Assessing the Efficacy of Indirect Estimates of Body Size in Asian Elephants

“…It is, however, more difficult to directly measure weight than other body parameters, so prediction equations are frequently used, though often without validation using known values of weight. We found chest girth, sometimes referred to as heart girth or thorax circumference in the literature, to be the best predictor of weight in Asian elephants, in line with previous studies on large mammals [ 14 , 17 , 28 , 59 – 61 ], and some of the other weight prediction equations for Asian elephants [ 36 , 37 , 39 ]. Whether the relationship between chest girth and body weight, and thus the equation used for predicting weight from chest girth, differs between distinct populations of a species is not known outside a few species, and there is no consensus: white-tailed deer Odocoileus virginianus populations differ in this relationship [ 59 ], though populations of the grizzly bear Ursus arctos may not [ 62 ].…”

“…We applied twenty-one prediction equations from five previous studies in the literature to data on the timber elephants in order to test whether they are applicable in the field for a different population than the one from which they were created. R 2 from these models ranged from 0.080 to 0.956 for these prediction equations, highest from Kurt and Garai’s [ 36 ] male equation ( R 2 = 0.956), which uses chest girth and height, and lowest from Sreekumar and Nirmalan’s [ 39 ] length-based equation ( R 2 = 0.080). The Kurt and Garai [ 36 ] equation for infants provides the most accurate fit ( R 2 = 0.814, mean±SD (%) = 99.3±7.7), though this only applies for elephants under the age of 6 ( Fig 2 , Table 2 ).…”

“…Colour of circles indicate which parameter was used in the equation. Letter codes in the x-axis labels are as follows: H = Hile et al [ 37 ]; KU = Kurt and Garai [ 36 ]; KA = Kanchanapangka et al [ 40 ]; SR = Sreekumar and Nirmalan [ 39 ]; SU = Sukumar et al [ 38 ]; G = Chest Girth; L = Length; N = Neck Circumference; F = Female only; M = Male only. Numbers represent the age range.…”

“… Grey bars represent the entire range of the equation and the red dashed line represents 5% above and below one. Letter codes in the x-axis labels are as follows: F = Female; M = Male; KU = Kurt and Garai [ 36 ]; HI = Hile et al [ 37 ]; KA = Kanchanapangka et al [ 40 ]; SR = Sreekumar and Nirmalan [ 39 ]; am = Age model equations (Eqs 1 and 3 ); rm = Reduced model equations (Eqs 2 and 4 ). Red circles represent females, and orange circles males.…”

A visual system for scoring body condition of Asian elephants (Elephas maximus)

“…The relationship between height and weight has been studied by many groups without considering BCS [Kurt and Nettasinghe, ; Sreekumar and Nirmalan, ; Sukumar et al, ]. Hile et al [] reported heart girth (chest girth) is the single best parameter to predict body weight.…”