Another new series!
I'm keeping Saturdays free for more Caturday posts - I haven't quite decided what else to write about, but you'll know when I do. Sundays, however, are fair game. So, Crocodilians it is!
The African Dwarf Crocodile (Osteolaemus tetraspis) is the smallest extant Crocodilian in the world. It can be found in the lowland tropics of sub-Saharan Africa and West Central Africa. Other names for it include the African dwarf, the bony crocodile or the broad-snouted crocodile. Osteolaemus comes from the Ancient Greek words for "bony" and "throat," and tetraspis means "four shields," describing the shield-like scales that cover the back of the African Dwarf Crocodile's neck.
Fully grown adult African Dwarf Crocodiles will reach an average total body length of about 4.9 feet (1.5 meters), although one extremely large specimen was recorded at 6.2 feet (1.9 meters). Males are larger than females, weighing up to 180 pounds (80 kg), while the females weigh only 88 pounds (40 kg).
Because of their small size (relative to other Crocodilians), the African Dwarf Crocodile has developed the four bony scales on the back of its neck, as well as on its belly, tail and the underside of its neck. These growths are called osteoderms, which means that this added protection grows in the dermal layers of the skin. They have about 32 teeth, which they use to feed on vertebrate animals, crustaceans, and sometimes carrion. They are nocturnal, shy creatures, and will spend the daytime hours in burrows dug at the edge of the water - sometimes the entrances to these burrows will be submerged.
There are currently two recognized subspecies of African Dwarf Crocodile:
- Osteolaemus tetraspis tetraspis
- Osteolaemus tetraspis osborni
O. t. osborni is also known as the Congo Dwarf Crocodile, or Osborn's Dwarf Crocodile. Genetic studies have indicated that there might be three distinct genetic populations, and some have argued that this means that the subspecies should be elevated to full species.
Female African Dwarf Crocodiles will build nesting mounds during the rainy season, typically May or June. Adults only interact closely with each other during this time of the year. Females will lay 10 to 20 eggs, watching over and incubating them for up to 105 days. It's unknown how long the females will watch over the hatchlings, which are only 11 inches (28 cm) long. During this time they are extremely vulnerable to predation by birds, fish, mammals and other crocodiles. African Dwarf Crocodiles are widely distributed, so it's likely that the overall population is healthy. However, so little is known about them that it's difficult to say for sure.