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In Gabon (Africa), known for its geological diversity and its fauna, scientists were surprised to discover orange crocodiles unique in the world, living among the droppings of bats in the caves .
"When I approached with my flashlight in the cave, I saw red eyes … crocodile! It was in 2008. Two years later, we have took a first specimen in the cave and we realized that it was orange, "recalls Richard Oslisly, geographer (archaeological sediment specialist)
.A team of investigators tried to find remains of human presence in the caves of Abanda, southern Gabon.
The "orange cavern crocodile" which can measure up to one meter 70 centimeters, is unique in the world and was seen in the caves of the African country, according to Oslisly.
"Initially, we thought that the color could be due to their diet, since we checked that these reptiles eat bats orange" says the French researcher But after more detailed studies, scientists have presented other hypotheses: a "depigmentation" caused by the lack of light in these caves or the harmfulness of "guano", a substance composed of bat droppings in which these animals move throughout their underground life.
"The urine of bats began to attack their skin and transformed their color" explains Olivier Testa, spelunker and member of the scientific team.
Oslisly, Testa and American researcher Matthew Shirley have been increasing scientific expeditions since 2010 to better understand these crocodiles.
When mapping the caves, they found four orange crocodiles on about 40 specimens of this "caveman" species.
Dozens of "normal" pigmentation crocodiles live in neighboring caves connected to the surface, says Testa, while orange specimens live in caves that can only be accessed by vertical shafts.
A Presence of 3,000 Years
"We believe that dozens of crocodiles settled in the caves of Abanda 3000 years ago, which corresponds quite well to a period when the sea level had fallen and in which "The orange crocodiles were probably trapped in the cave" after entering the corridors when they were small " and not being able to get out of there when they grow up, according to Oslisly.
Several More or less narrow and interconnected corridors form a network of caves in Abanda and are sometimes inundated by the rising waters of the water table.
Shirley maintains, however, that the crocodiles may have been settled in their cave by their own decision and that perhaps they are not trapped there.
In total darkness, these animals survive with a particular diet. In the caves there are no fish or shellfish, and they feed on bats, grbadhoppers and crickets. "It's a particularly demanding environment," says Shirley.
According to the researchers, these specimens, both orange and those of normal color, belong to the group of dwarf crocodiles "Osteolaemus tetraspis" and are "mutating".
The DNA of these specimens is not sufficiently different from the surface of their dwarf cousin to make a new species, says Shirley, but these animals have developed their own "genetic signature".
Cave crocodiles have, indeed, a unique group of genes pbaded down from generation to generation, scientists have found by comparing blood samples of troglodyte dwelling specimens with those of their living dwarf cousins only on the surface in Gabon
Although the crocodile is already a protected species in Gabon, Oslisly advocates that the caves of Abanda become a "entirely protected sanctuary".
"There is still much to discover in the caves of Abanda," says the geoarchaeologist, who hopes to promote "scientific tourism".
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