Social Dynamics of Exotic Dama Gazelles (Nanger dama) on Texas Ranch Land

Abstract

This project examines social dynamics of North African dama gazelles (Nanger dama ruficollis) under different combinations in a large, 202 ha, rangeland pasture in Central Texas, USA. There are many wildlife ranches in this part of Texas that keep herds of these critically endangered dama gazelles. Therefore, an increased understanding of how these pasture animals may assort themselves under different social combinations can not only help managers sustain and grow their herds but also bolster the numbers that give the species a better chance to remain viable while status in their native countries remains precarious. Investigated were: (1) 7 adult females with one adolescent male and one young adult male, (2) the same adult females and immature male without any adult males, (3) the same adult females and the young, now maturing, male with multiple adult males. It was shown that multiple adult males can co-exist in large pastures with minimal aggression, even when females are present, provided there is informed management. All the gazelles wore GPS-radio collars (7 adult females, 1 immature male, and 1-to-3 adult males depending on phase of the project). Locations were recorded every 3 hr. Visual observations were made monthly. Project duration was December 19, 2014, until June 30, 2016. Without the initial adult male, the female herd split and association values declined. With new adult males added, 2 divided the pasture, thus, separating spatially. The maturing male kept his core area where the main female group stayed, but now separated temporally. Adult males focused on areas favored by females but did not direct the movements of the females. These males did not associate as closely with females as females did with each other. Estimating maximum possible adult males for a pasture must allow for slope, vegetation density, and sites favored by females. The only two similar studies determined larger core areas under more xeric conditions, but these other studies could not assess group dynamics in detail without collars on more animals.