The Nile crocodile (Crocodylus niloticus) is one of the largest crocodiles among the four species found in Africa. Overall, it is the second largest crocodile in the world, next to the saltwater crocodile. There are many subspecies of the Nile crocodile that are found in regions other than Africa. The average lifespan of a Nile crocodile is about 45 years in wild and 80 years in captivity.
Nile Crocodile: Facts and Information
Habits and Habitat
Nile crocs are solitary in nature. At times though, they gather together to hunt their prey. They can survive in various types of habitats, including rivers, lakes, estuaries, freshwater swamps, brackish water, and so on. Adults are mostly seen digging dens with their snout and feet in order to protect themselves from the adverse environmental conditions of their habitat. Other than southern and tropical Africa, they are found on the Madagascar Island as well.
Juvenile Nile crocodiles are dark brown to olive in color, with dark cross-bands on their body and tail. In contrast, adults have darker and uniform colors with dark cross-bands, particularly on their tail. The cross-bands on their body fade away as they grow up. The belly is white, dull yellow, or gray in color. Their eyes are green and have nictitating membranes. Nile crocodiles are sexually dimorphic; males are about 30% larger than the females. The average body length for males is about 3.5 - 5 meters; 6 meters in rare cases. On the other hand, the average length for females is 4 meters. Reports suggest that they can even reach 7 meters at times. While male crocodiles weigh up to 500 kg, females are known to weigh about 350 kg.
The diet of juvenile Nile crocodiles ranges from small aquatic invertebrates to large vertebrates, such as fish, amphibians, and other reptiles. Adult crocodiles feed on fish, large cats, zebra, camel, porcupines, donkey, horses, buffaloes, antelope, young hippos, and so on. They have powerful jaws to hold their prey. Occasionally, Nile crocodiles are seen forming a semi-circle in cooperation across the river, so as to herd fish and later feed on them. These crocodiles attack the animals that come to drink water, drag them inside the water, and drown them. They smash their victims' backbone by delivering powerful blows using their tails, and impair their movement. At a time, they can eat up to half their body weight.
Very often, a Nile croc lies with its mouth open and birds, like the spur-winged plover, pick parasites and pieces of meat from between their teeth. One unusual habit is swallowing of stones, which helps them digest their food. It is believed that around 10 pounds of stones are found in a crocodile's stomach. Sometimes, they attack humans and feed on them . About 200 people are reported to die each year in the jaws of the Nile crocodile.
Male and female crocs reach sexual maturity at the age of 10 years, when males reach to 3 meters and females reach to 2.5 meters. During the mating season, males attract females by making a variety of actions, like bellowing, blowing water out of their nose, slapping their snouts in water, and making a variety of other noises. Around 2 months after mating, usually in the month of August and September, females lay 50 - 60 eggs in holes in the riverbank. Both male and female crocs guard the eggs until they hatch. Usually, they roll the eggs in their mouth in order to help the hatchlings emerge. After 70 - 100 days of incubation, hatchlings―about 10-inch long―emerge from the eggs. Female carries the babies to the water and takes care of them for 8 - 10 weeks.
Nile crocodiles are enlisted as 'Least Concerned' species by the International Union for Conservation of Nature (IUCN). On the other hand, they have been enlisted in Appendix I and Appendix II by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). According to a population survey, the estimated wild population of Nile crocodiles is in the range of 250,000 - 500,000.
The population of Nile crocodile is threatened by habitat destruction, pollution, and hunting by humans―for their skin and meat. In fact, recent studies reveal that the 'trifdid weed' (Chromolaena odorata)―a non-native invasive plant in South Africa―is threatening the existence of these reptiles by forcing them to abandon their nesting sites.