Comparative Morphometric Analysis Of Captive Jaguars Vs. Wild Jaguars (Panthera onca) In Venezuela

In Venezuela the oldest, although anecdotical, record known of a captive jaguar is a male in the city of Maracay between 1918 and 1935. Body measurements were made on 22 jaguars kept in Venezuelan zoos between 1996 and 2009 to provide data on external morphometrics and compare with the measurements of 25 free-living animals, published by Hoogesteijn and Mondolfi (1992) and determine whether there are significant differences in the morphology between sexes of captive and free-living animals. The evaluation of morphometric variation was focused on three body measurements and body weight: Head-and-body length (HBL) and Tail length (Tl). Total body length (TBL) was calculated by adding HBL and Tl. Body weight (BW) was determined using a clock scale to the nearest gramme/kilogram. To determine the values all animals were anesthetized. The sexes were analyzed separately. All data were used for the calculation of descriptive statistics. Student t-tests were used with a significance level 0.05 to establish if there is a significant difference between the measurements and weights of the sexes. The TBL and HBL in captive males were observed to be 8.78% and 12.13%, respectively, less than that of free-living males. A principal components analysis made it possible to assess the variability between HBL, TBL, and BW between sexes and between free-living/wild and captive animals. This study showed no significant differences in the BW of captives and wild females. Some captive males jaguars in this study may be thinner than normal, because of their diet and others may be fatter because of the lack of physical activity imposed by captivity. Body mass index (BMI) was used to contrast the difference in the average mass of each sex in both captive and free-living animals. Simple linear regressions and correlation coefficients were used to determine the relationship between body mass and male/female size. According to correlation coefficients, the change in weight that can be attributed to the ratio of weight to body length is 8.55 % for males and 9.83 % for females.