A dark shadow lurking just below the surface of a murky African lake or perhaps a motionless log drifting along with a river's current until, with lightning speed, the water is broken and a victim secured. Whatever the image, crocodiles awaken a primeval fear in all of us. These modern day monsters are so efficiently designed that they have changed very little in millions of years. Their lives are simplicity itself - eat, sleep and mate - but Africa's crocodiles face stiff competition for their food, habitat and suitable partners. Fortunately for them, these master predators have honed their skills over countless generations and have perfected a lifestyle that has ensured the survival of their species.