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In Gabon, known for its geological diversity and its fauna, scientists were very surprised to discover orange crocodiles, unique in the world living amidst bat droppings in the caves.
"When I approached with my flashlight in the cave, I saw red eyes … crocodile in 2008. Two years later, we released a first specimen of the cave and we realized that it was orange ", remember the geoarchaeologist (archaeological sediment specialist) Richard Oslisly
An extraordinary double discovery that occurred while he and a team of investigators were trying to find remains of human presence in the caves of Abanda, southern Gabon.
"The orange cavern crocodile, which can measure up to 1.70 m, is unique in the world and was only seen in the caves of the African country, according to Oslisly . " At first, we thought that the color could because of its we found that these reptiles ate orange bats, explains 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 its color," says 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. , found four orange crocodiles about 40 specimens of this species of "caveman"
Dozens of crocodiles with "non-metallic" pigmentation 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 where the sea level had fallen and that coastal area was again, "says Shirley
The orange crocodiles were probably trapped in the cave" after entering corridors when they were small "and could not get out of there when they grow up, according to Oslisly.
Several more or less 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 crocodiles may have been installed in their cave by their own decision and that maybe they are not trapped in this place.
In total darkness, these animals survive with a particular diet . In the caves there are no fish or shellfish, and they feed on bats, grasshoppers and crickets. "It's a particularly demanding environment," says Shirley
According to the researchers, these specimens, whether they are orange or normal, belong to the group of dwarf crocodiles "Osteolaemus tetraspis" and are "mutations"
. According to Shirley, the DNA of these specimens is not sufficiently different from the surface of their dwarf cousin to make a new species, but these animals have developed their own "genetic signature".
Crocodiles in caves have, indeed, a group of unique genes passed down from generation to generation, scientists have found by comparing blood samples of troglodyte dwelling specimens with those of their dwarf cousins living only on the surface in Gabon.
The crocodile is already a protected species in Gabon, Oslisly advocates that the caves of Abanda become a "fully protected sanctuary"
"There is still much to discover in the caves of Abanda" says the geoarchaeologist, who hopes to promote "scientific tourism".
Source: AFP
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