Kaziranga has the world's largest population (approximately 2200 nos.) of the great Indian one horned rhinoceros (Rhinoceros unicornis). The animal gets its name from the Greek words rhis - nose and keros - horn. The rhino is generally solitary, unless accompanied by a calf. Its life span is approximately 45 years and from six to eight years of age the female becomes capable of giving birth to a young one. Despite its bulk, the rhino can attain speeds up to 48 to 50 kms.
Kaziranga has over 1,000 Asian elephants. Kaziranga's wild elephant population is not static. Herds move along traditional migratory routes over long distances. Herds are led by matriarchs. Males are usually solitary, but may also be found in the company of a younger male. Early mornings and late afternoons are the preferred times to feed in the open. When the sun is high, they choose forested parts of their range where they will continue feeding on branches, leaves, barks and fruits. On an average, they weigh 3,000 kgs.
Kaziranga National Park is home to more than 110 tigers and is reputed to have the highest density of tigers in proportion to its core area. Sighting of tigers, though rare, is a majestic sight in the natural setting of Kaziranga's huge bio-diverse savanna grassland.
About 1,400 buffalo population is there in Kaziranga. Kaziranga harbours a crucial breeding population of buffalos. Sporting magnificent horns, perhaps the largest among all bovines in the world, wild buffalos are formidable opponents that can weigh over 1,000 kgs. Like rhinos and elephants, wild buffalo can be seen grazing in and around Kaziranga's many beels (swamps and small lakes) in the morning and afternoon. Males are essentially solitary though herds may comprise of a dominant male.
Approximately 500 Swamp Deer or Barasingha (twelve-horned deer), the largest population in Eastern India are there in Kaziranga. Swamp deer prefers grasslands with reed brakes and patches of tree forests.
Kaziranga is home to 35 species of mammals, 500 species of avifauna,60 species of reptiles , 24 species of amphibians,42 species of fishes , 440species of plants and 491 species of butterflies