Major attractions of Dudhwa National Park are the tigers (population 98 in 1995) and swamp deer (population over 1,600). Billy Arjan Singh successfully hand-reared and reintroduced zoo-born tigers and leopards into the wilds of Dudhwa. Some rare species inhabit the park. Hispid hare, earlier thought to have become extinct, was rediscovered here in 1984.
In the mid-1980s, Indian rhinoceros was reintroduced into Dudhwa from Assam and Nepal.
The other animals to be seen here include swamp deer, sambar deer, barking deer, spotted deer, hog deer, tiger, Indian rhinoceros, sloth bear, ratel, jackal, civets, jungle cat, fishing cat, leopard cat.
Dudhwa National Park is a stronghold of the barasingha. Around half of the world's barasinghas are present in Dudhwa National Park. Smaller than the sambar deer, the barasinghas have 12 antlers that collectively measure up to 100 cm (39 in). One can spot herd of these rare animals passing through open grasslands. Around half of the surviving population of Barasinghas is found in the park.
These animals are smaller than sambar deer and weigh around 180 kg. Due to their slightly woolly, dark brown to pale yellow cloak, the grasslands acts as the perfect camouflage.