Ten years ago, a team of scientists went exploring into the rainforest of Gabon, and ventured into a cave. In the pitch-black, bat-infested interior, the scientists came face to face with a terrifying creature with big glowing eyes and bright orange scales. It was a crocodile.
Crocodiles rarely inhabit caves, and this malevolent appearance threw the scientists off feet. Luckily, the creature was as surprised as the men, and it scurried off into the darkness. After exploring more than 600 meters of cavities, the researchers spotted a total of nine crocodiles living in inhospitable environment. There was no light inside the caves, everywhere there was bat droppings, and there was little to eat. They also found that some of the crocodiles were trapped inside by narrow openings and deep pits and with no way to get out.
Numerous expeditions to the Abanda caves have been carried out in the past ten years in an effort to better understand the origin of these cave-dwelling crocodiles. This is what we know till now.
The Abanda cave crocodiles are a species of the African dwarf crocodiles, which are found throughout West and Central Africa. They are the world’s smallest crocodile species averaging 1.5 meters in length. The cave-dwelling crocodiles, however, have many physical dissimilarities with their forest- and swamp-dwelling cousins. They have broader heads, have poor eyesight, and their skin has a strange orange hue. Researchers believe that years of soaking in bat-poop had discolored their skin, the same way crocodile leather manufacturers treat crocodile skin with chemicals to bleaches the skin off its dark color.
But the difference is more than skin deep. Researchers found their genetic signature is also different from their topside counterparts, which has lead researchers to believe that the crocodiles are undergoing mutation and is slowly transforming into a new species. Because these kind of changes require several hundred generations to accumulate in their DNAs, its believed that the crocodiles split off thousands of years ago from its outdoor relatives.
“Maybe it’s just the reproduction within a very small population,” explained Olivier Testa, one of the scientist studying the crocs. “If you take 100 human beings and you put them together for 1000 years, they start mutating because they just reproduce between themselves.”
It’s hard to say why they chose to live inside caves. Maybe they like bats, because that’s the only stuff the crocodiles get to eat, and crickets and algae. Occasionally, the juvenile crocodiles may leave their homes to explore the outside through various openings, but once the crocs hit a certain size they get trapped inside and have to spend the rest of their days in pitch-dark, feeding off bats and swimming in bat guano.
Photo credit: Olivier Testa
Comparison of a cave crocodile and a forest-dwelling one. Photo credit: Olivier Testa
Photo credit: Olivier Testa