The Nile Crocodile
The Nile crocodile, despite its name, is found in most parts of Africa and is the second largest crocodile in the world. Read more to know about the habitat, characteristics, feeding, reproduction and conservation of the Nile crocodile.
The Nile crocodile, scientific name Crocodylus niloticus, is one of the largest crocodiles among the four species found in Africa. Crocodylus means “crocodile” and niloticus means “belonging to the Nile River”. Overall, it is the second largest crocodile, next to saltwater crocodile. There are many subspecies of the Nile crocodile that are found in other regions other than Africa. The average life span of a Nile crocodile is about 45 years in wild and 80 years in captivity. They are voracious predators and can feed on any animals or humans.
Habit and Habitat: Nile crocs are solitary in habit, but sometimes they gather together for hunting their prey. They can survive in various habitats such as rivers, lakes, estuaries, freshwater swamps, brackish water and so on. Adults are mostly seen digging dens with their snout and feet, in order to stay and protect themselves during adverse environmental conditions. They are found in Madagascar and in tropical and southern Africa.
Physical Characteristics: Juvenile Nile crocodiles are dark brown to olive color with darker crossbands on the body and tail. Adults have darker and uniform colors with dark crossbands, particularly in the tail portion (the body crossbands fade away as they grow up). However, the belly is white, dull yellow or grey 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 of a male Nile crocodile measures about 3.5-5 meters (rarely 6 meters). Reports suggest that their body length can even reach to 7 meters. Male crocs weigh up to 500 kg. Female crocs reach to about 4 meters in body length and weigh about 350 kg.
Feeding: The food of juvenile Nile crocodiles includes smaller aquatic invertebrates to larger vertebrates such as fish, amphibians and other reptiles. Adult Nile crocs feed on fish, large cats, zebra, camel, porcupines, donkey, horses, buffaloes, antelope, young hippos and so on. Sometimes, they attack humans and consume as food (about 200 people are reported to die each year in the jaws of the Nile crocodile). 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. Nile crocodiles attack those animals that come to drink water, then dragged the animals inside water and drown them. They smash their victims’ backbone through powerful blows of their tails so that the victims can’t move. At a time, they can eat up to half of their body weight.
Very often, a Nile croc lies with its mouth open, so that birds such as spur-winged plover can pick parasites and pieces of meat from between the croc’s teeth. One unusual habit is swallowing of stones for digestion aid. It is believed that around 10 pounds of stones can be found in a crocodile’s stomach.
Reproduction: Male and female crocs reach sexual maturity at 10 years of age, when males reach to 3 meters and females reach to 2.5 meters, on an average. During the mating season, males attract females by making a variety of actions such as bellowing, blowing water out of their nose, slapping their snouts in water and by 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 to 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.
Conservation: Regarding conservation, Nile crocs are regarded as an endangered species, in consideration to the total distribution and population survey. It is a fact that population of Nile crocs in some specific regions is depleting and some of the subspecies are on the verge of extinction. Hence, in some African countries, Nile crocs are protected legally under International Union for Conservation of Nature and Natural Resources (IUCN) and Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Various threats to the population of Nile crocodile include habitat destruction, pollution and hunting by humans (for their skin and meat). According to a population survey, the estimated wild population of Nile crocodile is 250,000-500,000.
Recent studies have found out that in South Africa, one of the nonnative invasive plants known as the ‘trifid weed’ (Chromolaena odorata) is causing a threat to Nile crocodiles by making them abandon the nesting sites.
kaynak http://www.buzzle.com
Benzer Konular