The mighty Rufiji river and the lakes are the lifeblood of the park and during the dry season of July through October, it is the place where a huge concentration of wildlife gathers. Nyerere national park is arguably the best place in Africa to spot the once endangered African Hunting Dogs (wild dogs). There are fantastic elephant herds, plenty of lion prides, leopard, hyena, kudu, eland, impala, bush buck as well as hippo and huge Nile crocs in the river and lakes. The birdlife here is also phenomenal with over 400 recorded species. Wildlife migrates from the east and the south both resident and migratory.

The wildlife in the Selous is particularly interesting as it attracts both east and southern African wildlife, both resident and migratory, and over 400 known species of birds, which make it a key destination on a Southern Tanzania safari. Lion are particularly strong here and there are large numbers of leopard. The park is home to over 50% of the remaining endangered African wild dog, and also hosts very good populations of buffalo, giraffe, eland, hyena, sable, hippo, crocodile, kudu, baboon, wildebeest, zebra, impala, hartebeest, colobus and vervet monkeys along with over 400 species of bird.