The eastern region of Vidarbha contains Maharashtra's oldest National Park, the Tadoba Andhari Tiger Reserve, one of India's 39 Project Tiger Reserves. The National Park consists of two forested rectangles of the Tadoba and Andhari range. Aside from around 50 tigers, Tadoba Tiger Reserve is home to rare Indian wildlife like leopards, sloth bears, gaur, wild dogs, hyenas, civet, jungle cats, and many species of Indian deer such as sambar, cheetal, nilgai, and barking deer. The Tadoba lake sustains the Marsh Crocodile, which were once common across Maharashtra. Tadoba also has a varied diversity of aquatic birdlife. Thick hills form the northern and western boundary of the Tiger Reserve. To the southwest is Irai water reservoir which acts as a buffer between the park's forest and the extensive farmland.