The park is rich in wildlife - buffalo, hippo, baboons, sable antelope, lions, wild dogs, wildebeest, zebra, impala, giraffe, warthogs, and elephants which can easily be viewed all the year round. Reptiles including crocodiles, monitor lizards and pythons are also resident in the park as are over 400 recorded species of birdlife. Among the bird species are the colourful residents such as the lilac-breasted roller, yellow-throated long claw and bateleur eagle joined by a host of European migrants during the rainy season.
The main feature of the park is the Mkata Floodplain, along with the Uluguru and Lumango mountain ranges that border the park on two sides. Open grasslands dominate in the flood plain, eventually merging with the miombo woodland covering the lower hills. Mikumi forms the northern border of the Selous Game Reserve and is part of a vast wilderness ecosystem covering 75,000 sq km.