The National Park's many rivers, in addition to their important ecological functions, act as reservoirs of biodiversity. Remote and unspoilt, they contain a number of hippos, crocodiles, otters, and a wealth of fishes. Their forested banks support a variety of birds and larger mammals including pigs such as Giant forest hog, Red river hog, and warthog; antelopes such as kob, bushbuck, waterbuck, hartebeest, Red-flanked duiker, Yellow-backed duiker and the mighty buffalo; primates such as Black-and-white colobus monkey, Putty-nosed monkey and Mona monkey, the ever-present baboons as well as chimpanzee; carnivores such as leopard, Wild dogs and lion - a rare, but not impossible encounter. In the Northern parts of the park, elephants might be seen near the rivers.
The magnificent rivers are one of the park's best features and provide the basis for a number of spectacular walking tours. Arrange for guides, porters and ranger escorts either at Gashaka or Serti.
The River Kam is the park's largest river. In the dry season the crystal clear water is full of fish in addition to small groups of hippo and crocodile. During this time it is possible to follow the river upstream, southwards to the park boundary, returning to Gashaka village via Mai Idanu and Mayo Kpa, while passing through some marvellous woodlands and forests.
River Gashaka, which has its headwaters on the Sabere plateau, is another of the park's major rivers, and a tributary of the River Kam. From Gashaka village the river can be followed right up as far as the enclave of Mayo Sabere, passing through a ridge of forested mountains.
The River Gam-Gam can be followed from Gashaka to Yakuba via Mayo Ngiti and from there up to the Sabere plateau. Or, alternatively follow the course of the river itself to reach the remote Gam-Gam basin which forms the very heart of the park. The remote upper reaches of this river are spectacularly rugged.
The River Yim in the Northern Toungo sector is full of fish and smaller numbers of crocodiles and hippo. The river can be followed eastwards from Gumti village towards the Cameroonian border, through a series of deep narrow gorges and spectacular scenery, into the most remote corner of the park: the mountains of Tepel and Lenga, overlooking the small town of Deo-Deo in Cameroon.