Nile Crocodile (Crocodylus niloticus)
The Nile crocodile has a somewhat deserved reputation as a vicious man-eater. The proximity of much of its habitat to people means run-ins are frequent. And its virtually indiscriminate diet means a villager washing clothes by a riverbank might look just as tasty as a migrating wildebeest. Firm numbers are sketchy, but estimates are that up to 200 people may die each year in the jaws of a Nile croc.
Africa’s largest crocodilian, these primordial brutes reach a maximum size of about 20 feet (6 meters) and can weigh up to 1,650 pounds (730 kilograms). Average sizes, though, are more in the range of 16 feet (5 meters) and 500 pounds (225 kilograms). They live throughout sub-Saharan Africa, the Nile Basin, and Madagascar in rivers, freshwater marshes, and mangrove swamps.
The diet of the Nile crocodile is mainly fish, but it will attack almost anything unfortunate enough to cross its path, including zebras, small hippos, porcupines, birds, and other crocodiles. It will also scavenge carrion, and can eat up to half its body weight at a feeding.
One unusual characteristic of this fearsome predator is its caring nature as a parent.
Where most reptiles lay their eggs and move on, mother and father Nile crocs ferociously guard their nests until the eggs hatch, and they will often roll the eggs gently in their mouths to help hatching babies emerge.
Hunted close to extinction in the 1940s through the 1960s, local and international protections have helped them rebound in most areas. In some regions, though, pollution, hunting, and habitat loss have severely depleted their numbers.
West African Dwarf Crocodile (Ostelaemus tetraspis)
Dwarf crocodiles attain a medium adult length of 1.5 meters (5 feet), though the maximum recorded length for this species is 1.9 meters (6.2 feet). Adults are a uniform black on their backs and sides with a yellowish underside with black patches. Juveniles have a lighter brown banding on body and tails and yellow patterns on the head.
Dwarf crocodiles range across tropical lowland regions of sub-Saharan West Africa and West Central Africa.
The dwarf crocodile is a slow, timid, and mainly nocturnal reptile. As with all crocodilians, it is an adept predator of vertebrates, large invertebrates such as crustaceans and, when presented with the opportunity, also eats carrion.
Slender-snouted crocodile (Crocodylus cataphractus)
Slender-snouted crocodiles are native to freshwater habitats in central and western Africa. They are a medium sized crocodile and grow to about 3 to 4 meters long. They have a slender snout used for catching prey, hence their name. Their diet consists of mainly fish, snakes, amphibians and crustaceans.
Slender-snouted crocodiles begin to breed in the rainy season. The female constructs a mound nest consisting mainly of plant matter, which is sited usually on river banks. The eggs have a long incubation period, sometimes up to 110 days.
This species is generally not found in groups, except during the onset of the breeding season. The female constructs a mound nest consisting mainly of plant matter. Nests are sited on the banks of rivers, and construction generally begins at the onset of the wet season, although breeding is asynchronous even within members of one population. It has a similar, but generally shorter nesting season than that of the sympatric Osteolaemus tetraspis, which may nest further from the riverine habitat frequented by C. cataphractus.
American Alligator (Alligator mississippiensis)
The American alligator (Alligator mississippiensis), sometimes referred to colloquially as a gator, is a reptile endemic only to the Southeastern United States. It is one of the two living species of alligator, in the genus Alligator, within the family Alligatoridae. It is larger than the other extant alligator species, the Chinese alligator.
The American alligator inhabits wetlands that frequently overlap with human-populated areas.
Although primarily freshwater animals, alligators will occasionally venture into brackish water. Alligators live in wetlands and this is the vital habitat that holds the key to their continued long-term survival. Alligators depend on the wetlands, and in some ways the wetlands depend on them. As apex predators, they help control the population of rodents and other animals that might overtax the marshland vegetation.