Rusa is a genus of deer found primarily in Asia, particularly in regions like Southeast Asia and India. These deer are known for their large size and distinctive antlers, which can grow quite large in males. Rusa species are typically found in forests and grasslands, where they graze on a variety of vegetation. One of the most well-known species within this genus is the Sambar deer, which is often recognized for its dark brown coat and large body. Rusa deer are social animals, usually found in small herds, and they play an important role in their ecosystems by helping to maintain plant diversity through their grazing habits.