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African dwarf crocodile

Osteolaemus tetraspis

See large: African dwarf crocodile

Dwarf crocodiles are uniformly grey in colour. They are extremely ossified - ie the skin has extensive bony plates within it. Young crocodiles are yellow with dark bands. THe belly is also quite dark with this species. The jaws are blunt and broad, and the teeth protrude prominently.

There have long been two subspecies of dwarf crocodiles: one from the Congo (Osteolaemus tetraspis osborni), and the West African dwarf crocodile (O. t. tetraspis). Recently, scientists studying the group consider there to be 3 species: O. tetraspis, O. osborni, and O. cf. tetraspis - an as yet unnamed third species. The geographic seperation is that osborni is from the Republic of the Congo, the tetraspis form is from Gabon's Ogooue Basin, and the new form is the West African form. This is current research that is still being studied.

Where is it

Dwarf crocodiles inhabitat small, cool streams and pools in closed-canopy forest. It is also found in flooded forests, and in smaller pools off more open-canopied forest streams. The dark colouration and small size allows it to remain concealed in these pools. They are quite terrestrial, and move about overland, seeking refuge often in burrows or dens during daylight hours. They are largely nocturnal hunters.

Mating and breeding

This species is a mound nester. Leaves and other vegetation are scraped together into a mound against the base of a tree. Within this nest, the female lays around 14 eggs. Nesting is timed to coincide with the start of the wet season in some parts of the range, but varies between localities, and multiple clutches are suspected to be a possibility. Dwarf crocodiles certainly display parental care, including carying young to the water from the nest and protecting the hatchlings, at least for several weeks. The male is known to be involved in this activity from captive pairs.

Diet

Dwarf crocodiles mainly eat invertebrates and crustaceans - gastropods and crabs etc. The remainder is made up of fish and frogs, as well as small mammals. But even with larger animals insects seem to form a large part of the diet. Diet will vary according to the available prey in the area, as the diet is generalised, as for other crocodilians.

Status in nature

As with the dwarf caiman, dwarf crocodiles were not targeted by hunters during the large scale hunting for skins that occured in the 1900s. Now, the main threat faced by dwarf crocodiles is the bushmeat trade. Now that roads and infrastructures are making the areas more accessible, and the dwarf crocodile can be transported live across reasonable distnaces, it is targeted by the bushmeat trade for sale in markets throughout its range.

This trade is quite extensive, and is causing local depletions of many species of animals. One priority for dwarf crocodile conservation is to explore the feasibility of large-scale captive breeding to supply this bush meat trade. Such a breeding program would relieve pressure on wild populations, whilst still providing meat for the markets.

Logging and deforestation are also a threat, but this threat is secondary to the bush meat trade.

Conservation priorities include the above-mentioned captive breeding potential, surveys throughout the range to determine status and strong-holds of the species, and also to finalise the taxonomy of these crocodiles. Since Gabon and the Congos are possible strongholds of two species of the dwarf crocodile, this area needs to be studied to check sustainability of the current harvesting levels, and to ensure that sustainable limits are established. Also, basic studies on dwarf crocodile biology are needed, as it has been a little-studied species thus far.