Wildlife spotting is one of the best things to do in Sri Lanka. It has many reservations and wildlife parks, most of which have safaris. If you want to do an exclusive trip of these, you can talk to an experienced agent like Tangerine Tours and have them arrange one for you. You can see leopards, elephants, wild buffalos, wild bears, deer, sambars, peacocks, and many migratory birds in these national parks. There are distinct safari times and the parks are closed during certain parts of the year. So having someone guide you in this would be useful.