Sumbu protects populations of elephant, and a range of antelope including blue-and yellow-backed duiker, Lichtenstein's hartebeest, roan, sable, bushbuck, waterbuck, sitatunga, a few zebra and a large number of puku. Buffalo herds range up to about 400 individuals, and move around between Sumbu and the neighbouring GMA. The park's main natural predators are lion and leopard. Although poachers continue to kill occasionally, the animal populations are increasing.

A study in 1993–94 concluded that there were still wild dogs in the park, and its surrounding GMAs, though their continued long-term survival was in doubt. I don't know of reports of wild dog since then.

Although Sumbu cannot yet boast huge herds of the larger antelope, elephant or buffalo, there is sufficient game to make a trip to the park worthwhile. Its vegetation and environment are, on the whole, in pristine condition and offer a real Zambian wilderness experience.

The birding is good, and a number of East African species occur here that you won't find in the rest of southern Africa. Look out especially for the bare-faced go-away bird, common on the open floodplain areas; also a waxbill known as the red-cheeked cordon bleu, occasional ospreys, palmnut vultures and red-faced crombecs. Pel's fishing owl and bat hawks also occur, though not more commonly than elsewhere.

In the lake itself, there are plenty of hippos and a very healthy population of crocodile. Some are sufficiently large to dissuade you from even thinking of dipping your toe in the water.