Colloquial (Common) Names: Nylkrokodil (Afrikaans); kwena (Setswana); ingwenya (isiXhosa); ingwenya (isiZulu); Nilkrokodil (German).
Taxonomy: Class: Reptilia; Order: Crocodylia; Family: Crocodylidae.
Identification: Grey to olive-brown skin; raised scales on back in geometrical rows; bony plates called osteoderms found under the horny scales; eyes, ears and nostrils occur high up on head; pointy teeth prominent.
Size: Adult females average 2.5-4.5m and weigh 350-650kg; large males can reach 6m and weigh over 1 000kg.
Distribution: From northern KwaZulu-Natal to Swaziland and Mpumalanga lowveld, Limpopo, northern Gauteng and northern parts of North West Province.
Habitat: Rivers, dams and lakes in the Savanna and Indian Ocean Coastal Belt Biomes.
Activity & Behaviour: Nocturnal and diurnal; aquatic; fond of basking on riverbanks.
Diet & Feeding: Ambush predators feeding on insects; frogs (including tadpoles); fish (including sharp-tooth catfish); birds; various mammals including monkeys, antelope (like impala), wildebeest and zebra. Will also scavenge on hippo carcasses and known to attack and eat humans.
Reproduction: Oviparous – females lay 9-90 eggs. Incubation takes about 70-90 days. Females protect the nest site during incubation. Temperatures between 31-34°C produce males and 26-30°C produce females. Hatchlings measure 280-320mm.
Conservation Status: Vulnerable (due to habitat destruction, pollution and illegal hunting).
References and Recommended Further Reading:
- Alexander, G. & J. Marais. 2007. A Guide to the Reptiles of Southern Africa. Struik Nature.