Crocodile

Species

There are 5 species of crocodiles in Africa.

Crocodylus niloticus
Crocodylus suchus
Mecistops cataphactus
Mecistops leptorhynchus
Osteolaemus tetraspis

Nile crocodile
West African or Desert crocodile
West African slender-snouted croc
Central African slender-snouted croc
African dwarf crocodile

Population

The Nile crocodile has been assessed as Least concern with numbers between 50,000 and 70,000. The West African crocodile is a reasonably newly recognised species (2011) and has not been assessed by the IUCN yet. DNA testing show they are distinctly different and even ancient Egyptians knew this!
The West African slender-snouted crocodile was assessed in 2013 as Critically Endangered, with decreasing numbers. Estimates are possibly 500. The Central African slender-snouted crocodile has been considered a separate species since 2018 and has not yet been assessed.
In 1996, the African dwarf crocodile was assessed as being Vulnerable.

Size

The Nile crocodile is the largest in Africa, and second largest in the world growing to around 3 - 4.5 metres long and weighing around 225kg. Some have been know to grow over 6 metres long and weigh over 1,000 kg!
The West African crocodile typically measures 1.5 - 2.5 metres in length, although some can grow to 4m.
The slender-snouted crocodiles measure 3 - 4 metres and weigh up to 230 kg.
The African dwarf crocodile is the smallest crocodile in the world measuring 1.5 metres in length (but can grow up to 1.8 metres) and weigh 18 - 32 kg.

Habitat & distribution

Nile crocodiles are found in sub-Saharan Africa, the Nile basin and Madagascar living in rivers, fresh water marshes and mangroves.
Western crocodiles are found west of the middle of the Democratic Republic of Congo. They prefer lagoons, wetlands in forested areas, river basins and mangroves but these crocodiles have been found living in caves (in Mauritania).
The slender-snouted crocodiles have distinct populations - the Western species is found west of Cameroon and the central species to the east of Cameroon to DRC. The volcanic area of Cameroon provided a natural barrier for the two species to diverge 8 million years ago.
The African dwarf crocodile is found in West Africa.

Snap!!! Built for stealth and power

Crocodiles have many adaptations that make them a stealthy predator.
They have a long streamlined body, with short legs (to keep them low to the ground) and a powerful tail.
With eyes, ears and nostrils on top of the head, they are able to stay almost fully submerged.
Their skin is made of tough scales and they have bony plates (called scutes) lining the back and tail. Their colouration provides good camouflage.
And how about that mouth full of teeth - 64 to 68 to be precise. If they break, they are replaced - a crocodile might go through 8,000 teeth in their lifetime!
You don't want to be caught in their jaws. The bite force of a Nile croc can be a whopping 22,000 Newtons! A lion's bite is only 4,450 Newtons (not much stronger than a dog's).

Diet

The Nile crocodile is an apex predator. Any animal is on the diet if the croc can catch it by surprise. However, they mostly eat antelope, especially gazelle. Birds, fish, amphibians and invertebrates are also on the menu with the size of the prey increasing as the crocodile's size increases.
Slender-snouted crocodiles mainly eat fish.

Interesting facts

~ The Nile crocodile is more aggressive than the Western crocodile.
~ The West African slender-snouted croc has larger, heavier scales and rougher skin than the Central African slender-snouted croc, which has a softer, smoother appearance. The Central African slender-snouted croc also lack the bony skull crests.

Group

On land, a group of crocodiles is called a bask and in the water, they are called a float.

Breeding & lifespan

Females can lay 25-80 eggs in a nest on a riverbank. They are then covered with sand to make a mound. She will guard them until they hatch after about 90 days. The nest mound temperature determines the gender of the crocodiles. If the nest temperature is constantly <30°C, they will be mostly female; a temperature of 31°C produces a mix of genders and a temperature of 32°C will produce mainly males.
Baby crocodiles have an egg tooth which helps them break out of the shell. The hatchlings chirp and the mother may even help the hatchling by rolling the egg around in her mouth. The mother carries the hatchlings to the water and they will stay with her for several months.
Crocodiles can live to around 75 years in the wild.

Predators & threats

While crocodiles have no natural predators, humans hunted crocodiles for their meat and skin. Pressure on habitats is a threat to crocodiles.