page_title: Nile crocodile
section_title: Size and sexual dimorphism
hierarchical_section_title: Nile crocodile / Characteristics and physiology / Size / Size and sexual dimorphism
caption_attribution_description: The Nile crocodile or common crocodile (Crocodylus niloticus) is an African crocodile
context_page_description: The Nile crocodile is a large crocodilian native to freshwater habitats in Africa, where it is present in 26 countries. Due to its widespread occurrence and stable population trend, it has been listed as Least Concern on the IUCN Red List since 1996. It is widely distributed throughout sub-Saharan Africa, occurring mostly in the central, eastern, and southern regions of the continent, and lives in different types of aquatic environments such as lakes, rivers, swamps, and marshlands. Although capable of living in saline environments, this species is rarely found in saltwater, but occasionally inhabits deltas and brackish lakes. The range of this species once stretched northward throughout the Nile, as far north as the Nile delta. On average, the adult male Nile crocodile is between 3.5 and 5 m in length and weighs 225 to 750 kg.
  However, specimens exceeding 6.1 m in length and weighing up to 1,089 kg have been recorded. It is the largest freshwater predator in Africa, and may be considered the second-largest extant reptile in the world, after the saltwater crocodile. Sexual dimorphism is prevalent, and females are usually about 30% smaller than males.
context_section_description: Like all crocodiles, they are sexually dimorphic, with the males up to 30% larger than the females, though the difference is considerably less compared to some species, like the saltwater crocodile. Male Nile crocodiles are about 30 to 50 cm (12 to 20 in) longer on average at sexual maturity and grow more so than females after becoming sexually mature, especially expanding in bulk after exceeding 4 m (13 ft 1 in) in length. Adult male Nile crocodiles usually range in length from 3.3 to 5.0 m (10 ft 10 in to 16 ft 5 in) long; at these lengths, an average sized male may weigh from 150 to 700 kg (330 to 1,540 lb). In Limpopo, South Africa, males reportedly average 527 kg (1,162 lb). Very old, mature ones can grow to 5.5 m (18 ft 1 in) or more in length (all specimens over 5.5 m (18 ft 1 in) from 1900 onward are cataloged later). Mature female Nile crocodiles typically measure 2.2 to 3.8 m (7 ft 3 in to 12 ft 6 in), at which lengths the average female specimen would weigh 40 to 250 kg (88 to 551 lb).
  The bulk and mass of individual crocodiles can be fairly variable, some animals being relatively slender, while others being very robust; females are often bulkier than males of a similar length. As an example of the body mass increase undergone by mature crocodiles, one of the larger crocodiles handled firsthand by Cott (1961) was 4.4 m (14 ft 5 in) and weighed 414.5 kg (914 lb), while the largest specimen measured by Graham and Beard (1973) was 4.8 m (15 ft 9 in) and weighed more than 680 kg (1,500 lb). In attempts to parse the mean male and female lengths across the species, the mean adult length was estimated to be reportedly 4 m (13 ft 1 in) in males, at which males would average about 280 kg (620 lb) in weight, while that of the female is 3.05 m (10 ft 0 in), at which females would average about 116 kg (256 lb). This gives the Nile crocodile somewhat of a size advantage over the next largest non-marine predator on the African continent, the lion (Panthera leo), which averages 188 kg (414 lb) in males and 124 kg (273 lb) in females, and attains a maximum known weight of 313 kg (690 lb), far less than that of large male crocodiles.
  Evidence exists of Nile crocodiles from cooler climates, like the southern tip of Africa, being smaller, and may reach maximum lengths of only 4 m (13 ft 1 in). A smaller population from Mali, the Sahara Desert, and elsewhere in West Africa reaches only 2 to 3 m (6 ft 7 in to 9 ft 10 in) in length, but it is now largely recognized as a separate species, the West African crocodile.
caption: Groupings of crocodiles like this can include crocodiles of various sizes, but seldom of less than 2 m (6 ft 7 in), lest a cannibalistic large specimen launch an attack.
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