Imagine entering a new cave system deep in the central African rainforest, knowing you are one of the first humans to experience this territory. While you’re exploring the bat-filled, cramped corridor, you come face to face with two glowing red eyes!

No this isn’t the new plot of a B action horror movie. Crocodiles were found living permanently in a huge Africa cave system.

 

Olivier Testa is a speleologist, cave explorer, who came face to face with a cave-dwelling crocodile as he was exploring the Abandon cave system in Gabon, Africa.  In 2010, Olivier was on an expedition into the Abandon cave system following a tip that dwarf crocodiles had made these caves their permanent home.  Crocodiles generally only go underground for short periods if there is a drought on the land; therefore, it was highly unusual to find these crocodiles making a permanent home underground.    The explorers had to enter this cave system via a 22 foot deep pit.  The team thinks there were other entrances but they’ve since been filled in with sediment, trapping the crocs underground.

Orange crocs being pulled from the slurry they swim in!
Orange crocs being pulled from the slurry they swim in!

These crocodiles live and hunt for food in complete darkness; yet the young cave crocodiles, in particular, were found to be much healthier and in better body condition than the nearby forest crocodiles.   Crickets, bats, insects and algae are the food items the cave crocs can choose from in comparison to the frogs, shrimp, and crabs the forest crocs eat.  Bats and insects are so prevalent; they are continually dropping into the water allowing the crocodiles easy pickings.  Food is far more scarce aboveground in the forest.  How the crocodiles came to dwell in the caves initially is still up for debate. Were the crocs scavenging for food?  Were the crocs avoiding predators? Did climate change trap the crocs in the cave? More testing and expeditions are being planned to answer these questions.

The orange crocodiles look very similar to the African dwarf crocodile, Osteolaemus tetraspis, but a DNA test given in 2010 showed the cave-dwelling crocs differed by several percentage points to their forest cousins.  This DNA difference led the team to hypothesize that these orange crocs have been isolated in the cave system for thousands of years.  The cave crocodiles were broader, mostly blind and had orange colored skin.  Matthew Shirley, from the Rare Species Conservatory Foundation,  hypothesizes that the crocodiles are orange-colored because the water the crocs swim in is filled with bat droppings causing the water to be very basic.  The basic water eventually deteriorates the skin, turning it orange.

With over 3 miles of cave system to explore, the team thinks there could be over 50 crocodiles living in darkness underground.

gabon-on-map2

Credit:  http://www.abanda-expedition.org/

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