The Osteolaemus tetraspis osborni hails from the upper Congo region and can be found mainly in the Ituri Forest. This subspecies lacks the swollen appearance of the Broadface. During the day they often lie at the water's edge in large numbers, sunning themselves. At night they retreat to the water, where they live solitary lives and establish individual territories. Crocodiles and alligators are most at home in the water but are able to travel on land by sliding on their bellies, stepping along with their legs extended, or galloping awkwardly.
Large adults can stay underwater for over an hour without breathing.
They swim primarily by snakelike movements of their bodies and by powerful strokes of their muscular, oarlike tails, which are also effective weapons. A crocodile can also open its mouth when in the water due to a special valve in its throat. It allows the jaws to open without allowing water to move down the throat. When crocodiles float in the water, they leave only their nostrils, eyes, and ears above the surface. Their eyes can be covered with semitransparent membranes, much like a third eyelid and the ears and nostrils can be closed over by folds of skin.