Udawalawe is an important habitat for Sri Lankan elephants, which are relatively easy to see in its open habitats. Many elephants are attracted to the park because of the Udawalawe reservoir, with a herd of about 250 believed to be permanently resident. TheUdawalawe Elephant Transit Home was established in 1995 for the purpose of looking after abandoned elephant calves within the park. A total of nine calves, on two occasions in 1998 and 2000, with another eight calves in 2002, were released in the park when old enough to fend for themselves.
The rusty-spotted cat, fishing cat and Sri Lankan leopard are members of the Felidae family present in Udawalawe. The Sri Lankan sloth bear is seldom seen because of its rarity. Sri Lankan sambar deer, Sri Lankan axis deer, Indian muntjac, Sri Lankan spotted chevrotain,wild boar and water buffalo are among other mammal species. Golden jackal, Asian palm civet, toque macaque, tufted grey langur andIndian hare also inhabit the park. A study conducted in 1989 found that considerable numbers of golden palm civets inhabit the forests of Udawalawe. Five species of mice also have been recorded from the park. The endemic Ceylon spiny mouse, known from Yala National Park, was recorded in Udawalawe in 1989. Indian bush rat and three species of mongoose are also recorded in the national park.