Periyar, with its huge reservoir and dark tree trunks sticking out of the water, offers visitors an extremely picturesque landscape in which to view its abundant wildlife. However, the 26 sq km lake is only a small part of the reserve, which is spread across 777 sq km. Periyar has a large variety of animal species, of which the most sought after but least seen is the tiger. Large herds of elephants and bison are another major attraction. The reserve, with over 300 species, attracts a lot of birdwatchers. Another attraction is the over 120 species of butterflies. Most visitors enjoy sighting animals from the comfort of boats on the lake. The more adventurous ones undertake treks through the park. The eco-tourism infrastructure in southern India is definitely the best at Periyar.