**1. Introduction**

The assessment of population is the key to understand the demography of animals and for evaluating management effectiveness. Therefore monitoring of population is a crucial component in animal ecology and wildlife conservation. Evaluation of population density and biomass have been used to investigate the complex relationship between a species and its environment [1] and their inter-specific relationship in a community [2]. Management strategies in protected areas must be based on an understanding of the functional relationship between habitat conditions, animal population and the dynamics of these populations. Large herbivores are particularly difficult to conserve, because of their relatively low population densities, unique habitat needs, crop raiding tendencies and their consumption and disturbances due to people [3]. However, herbivores' conservation is crucial because apart from being important economic, nutritional and aesthetic resources, large herbivores directly or indirectly influence forest structure, regeneration and predatory species [4].

They also plays an important role in conservation of large carnivore population, especially tigers. Furthermore, the selective predation of particular prey species, age and size class allowed the coexistence of three carnivores [5–7]. The coexistence of Tigers and Leopard in the tropical forest was due to the specialisation on different sized prey species [7] or based on spatial or temporal partitioning of resources [8]. Therefore it is important to identify the available prey species and their role in shaping the community structure of the carnivores.

Mudumalai Tiger Reserve is part of Nilgiri biosphere reserve with contiguous forest area of about 5520 km2 , supports largest Asian elephant population in India [9]. Study area has heterogeneous habitat, ranging from tropical moist deciduous to thorn forest. These habitats differ in their extent of cover and support diverse ungulate and primate species [10]. This area also supports the highest gaur population in India [11, 12]. The gaur population had recovered significantly since the outbreak of Rinderpest epidemic in the mid 1960s which nearly wiped out the MTR population [13]. The present study provides baseline data on age-sex composition of elephant, gaur, and other mammal species. Our main objective is to obtain base-line estimates of population density and age-sex composition in the area to enable the formulation of viable management strategies.
