Crocodile
One of the three species of crocodile found in Africa, the Nile crocodile is the second largest crocodile in the world and inhabits larger rivers, lakes, estuaries and swamps in sub-Saharan Africa, the Nile basin and Madagascar.
Physical characteristics
The Nile crocodile is characterized by its four short, splayed legs, a flat, powerful tail, a scaly hide and a strong jaw.
Considerable variation exists throughout the range of the Nile Crocodile. Generally, it is a large crocodilian, averaging 5 m in length but reportedly reaching 6 m in rare instances. There are dubious reports of 7 m animals having existed, but these are hard to verify. The Nile crocodile (Crocodylus niloticus) is an African crocodile and may be considered the second largest extant reptile in the world, after the saltwater crocodile (Crocodylus porosus).
There is some evidence that Nile Crocodiles in cooler countries reach slightly smaller adult sizes (4 m). There are two known population of dwarf Nile crocodiles living on the extreme limits of the species' range, in Mali and even the Sahara Desert! Due to suboptimal conditions, adults average between 2 and 3 meters. Juveniles are dark olive brown with black cross-banding on the tail and body. This banding becomes fainter in adults.
Behavior
Habitat
South Africa, Botswana, Egypt, Ethiopia, Ivory Coast, Kenya, Madagascar, Mozambique, Namibia, Somalia, Swaziland, Zambia, Zimbabwe. The Nile crocodile is the most common crocodilian in Africa today and may be seen throughout much of the continent.
Diet
Although the juveniles are generally restricted to eating small aquatic invertebrates and insects, they soon move onto larger vertebrates such as fish, amphibians and reptiles. Adults, however, can potentially take a wide range of large vertebrates, including antelope, buffalo, young hippos, and large cats. Fish and smaller vertebrates often form the greatest part of their diet, however they have a reputation as being man-eaters, they have probably killed more people than all other crocodilian species combined.
Along with hippos and lions, crocodiles account for perhaps a few hundred deaths and disappearances each year, although exact figures are very hard to verify. Nile crocodiles will also often scavenge from carcasses, together with a number of other animals, all of which seem to tolerate each other’s presence. Several prey animals have been found wedged under submerged branches and stones, leading to reports that the crocodiles store unwanted prey here until a later date.
Some claim that it is necessary for the prey to decompose before the crocodiles are able to tear portions of flesh off, but this is unlikely to be true. The flesh may become softer if the prey remains in water after death, but crocodiles will certainly avoid rotting meat. When feeding, a number of individuals will hold onto a carcass with their powerful jaws whilst twisting their bodies.
The anchorage provided by the other individuals allows large chunks to be torn off for easier swallowing. Other cooperative feeding behavior has been reported, such as the action of many animals to cordon off an area of water to concentrate fish within. A hierarchy of feeding order is often observed in such situations, with more dominant animals feeding first.
Did you know?
Sources:
http://www.krugerpark.co.za/africa_crocodiles.html
http://www.nationalgeographic.com/animals/reptiles/n/nile-crocodile/
https://www.nature.org/newsfeatures/specialfeatures/animals/reptiles/nile-crocodile.xml
One of the three species of crocodile found in Africa, the Nile crocodile is the second largest crocodile in the world and inhabits larger rivers, lakes, estuaries and swamps in sub-Saharan Africa, the Nile basin and Madagascar.
Physical characteristics
The Nile crocodile is characterized by its four short, splayed legs, a flat, powerful tail, a scaly hide and a strong jaw.
Considerable variation exists throughout the range of the Nile Crocodile. Generally, it is a large crocodilian, averaging 5 m in length but reportedly reaching 6 m in rare instances. There are dubious reports of 7 m animals having existed, but these are hard to verify. The Nile crocodile (Crocodylus niloticus) is an African crocodile and may be considered the second largest extant reptile in the world, after the saltwater crocodile (Crocodylus porosus).
There is some evidence that Nile Crocodiles in cooler countries reach slightly smaller adult sizes (4 m). There are two known population of dwarf Nile crocodiles living on the extreme limits of the species' range, in Mali and even the Sahara Desert! Due to suboptimal conditions, adults average between 2 and 3 meters. Juveniles are dark olive brown with black cross-banding on the tail and body. This banding becomes fainter in adults.
Behavior
- Social behavior in Nile Crocodiles is often underestimated, although there are many aspects still poorly understood.
- It has been observed that social status may influence an individual's feeding success, with less dominant animals tending to eat less in situations where they come into frequent social contact with other, more dominant individuals.
- Groups of Crocodiles will often move onto land to scavenge from kills made up to several hundred meters from the water.
- Adults have also been observed fishing using their bodies and tails to corral the fish towards the bank where they are concentrated and picked up with a sideways snatch of the jaws.
- Both males and females have been reported to assist hatching by gently cracking open eggs between their tongue and upper palate.
- Hatchlings remain close to the juveniles for up to two years after hatching, often forming a crèche with other females. As with many Crocodilians, older juveniles tend to stay away from older, more territorial animals.
- Despite the vigilance of the female during the incubation period, a high percentage of nests are raided by a variety of animals, from hyenas and monitor lizards to humans.
- This predation usually occurs when the female is forced to leave the nest temporarily in order to thermo-regulate by cooling off in the water.
- Nile crocodiles are apex predators throughout their range.
- In the water, this species is an agile and rapid hunter relying on both movement and pressure sensors to catch any prey unfortunate enough to present itself inside or near the waterfront.
- Out of water, however, the Nile crocodile can only rely on its limbs, as it gallops on solid ground, to chase prey.
- No matter where they attack prey, this and other crocodilians take practically all of their food by ambush, needing to grab their prey in a matter of seconds in order to succeed.
- Like other crocodilians, it can bite but cannot chew, which is awkward when hunting larger prey. As a solution, the Nile crocodile drags large prey underwater, using a twirling method, called a “death roll,” to tear off large chunks of flesh.
- The crocodile’s mouth is filled with 68 teeth and is capable of exerting impressive force while clamping onto prey.
Habitat
South Africa, Botswana, Egypt, Ethiopia, Ivory Coast, Kenya, Madagascar, Mozambique, Namibia, Somalia, Swaziland, Zambia, Zimbabwe. The Nile crocodile is the most common crocodilian in Africa today and may be seen throughout much of the continent.
Diet
Although the juveniles are generally restricted to eating small aquatic invertebrates and insects, they soon move onto larger vertebrates such as fish, amphibians and reptiles. Adults, however, can potentially take a wide range of large vertebrates, including antelope, buffalo, young hippos, and large cats. Fish and smaller vertebrates often form the greatest part of their diet, however they have a reputation as being man-eaters, they have probably killed more people than all other crocodilian species combined.
Along with hippos and lions, crocodiles account for perhaps a few hundred deaths and disappearances each year, although exact figures are very hard to verify. Nile crocodiles will also often scavenge from carcasses, together with a number of other animals, all of which seem to tolerate each other’s presence. Several prey animals have been found wedged under submerged branches and stones, leading to reports that the crocodiles store unwanted prey here until a later date.
Some claim that it is necessary for the prey to decompose before the crocodiles are able to tear portions of flesh off, but this is unlikely to be true. The flesh may become softer if the prey remains in water after death, but crocodiles will certainly avoid rotting meat. When feeding, a number of individuals will hold onto a carcass with their powerful jaws whilst twisting their bodies.
The anchorage provided by the other individuals allows large chunks to be torn off for easier swallowing. Other cooperative feeding behavior has been reported, such as the action of many animals to cordon off an area of water to concentrate fish within. A hierarchy of feeding order is often observed in such situations, with more dominant animals feeding first.
Did you know?
- The mouths of Nile crocodiles are filled with 64 to 68 sharply pointed, cone-shaped teeth (about a dozen less than alligators have).
- For most of a crocodile's life, broken teeth can be replaced.
- The bite force exerted by an adult Nile crocodile has been shown by to measure 5,000 lbf (22 kN). However, the muscles responsible for opening the mouth are exceptionally weak, allowing a person to easily hold them shut with a small amount of force or to use duct-tape to adhere the jaws together even in large crocodiles.
- The stomachs of brooding females are always empty, meaning that they can survive several months without food.
- The Nile crocodile mostly hunts within the confines of waterways, either attacking aquatic prey or terrestrial animals when they come to the water to drink or to cross.
- The crocodile mainly hunts land animals by almost fully submerging its body underwater.
- Occasionally, a crocodile quietly surfaces so that only its eyes (to check positioning) and nostrils are visible, and swims quietly and stealthily towards its mark. The attack is sudden and unpredictable.
- The crocodile lunges its body out of water in practically the blink of an eye and grasps its prey.
Sources:
http://www.krugerpark.co.za/africa_crocodiles.html
http://www.nationalgeographic.com/animals/reptiles/n/nile-crocodile/
https://www.nature.org/newsfeatures/specialfeatures/animals/reptiles/nile-crocodile.xml