Why are these gray African crocodiles turning orange?

By Chris Giles, CNN

Updated 0926 GMT (1726 HKT) March 2, 2018

These orange cave-dwelling crocodiles, which can be found in the Abanda caves in a remote region in Gabon, could be mutating into a new species. They were first discovered in 2009.
Photos: Why are these African crocodiles orange?
Orange crocodiles – These orange cave-dwelling crocodiles, which can be found in the Abanda caves in a remote region in Gabon, could be mutating into a new species. They were first discovered in 2009.
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It remains a mystery why the crocodiles are orange, but scientists best guess is that acidic bleaching from bat feces could be the cause.
Photos: Why are these African crocodiles orange?
Orange crocodiles – It remains a mystery why the crocodiles are orange, but scientists best guess is that acidic bleaching from bat feces could be the cause.
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Tasty? The orange crocodiles think so. Their diet mainly consists of bats and crickets, different to forest crocodiles.
Photos: Why are these African crocodiles orange?
Bats – Tasty? The orange crocodiles think so. Their diet mainly consists of bats and crickets, different to forest crocodiles.
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The chest of the crocodile. Most African dwarf crocodiles are a grayish color.
Photos: Why are these African crocodiles orange?
Orange crocodiles – The chest of the crocodile. Most African dwarf crocodiles are a grayish color.
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The orange crocodiles were some of largest dwarf crocodiles expert Matt Shirley had ever found, at 1.7 meters.
Photos: Why are these African crocodiles orange?
Orange crocodiles – The orange crocodiles were some of largest dwarf crocodiles expert Matt Shirley had ever found, at 1.7 meters.
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A juvenile crocodile being documented.
Photos: Why are these African crocodiles orange?
Orange crocodiles – A juvenile crocodile being documented.
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orange crocodiles gabon 1orange crocodiles gabon 2orange crocodiles gabon 3 batsorange crocodiles gabon 4orange crocodile gabon 6orange crocodiles gabon 5

Story highlights

  • Genetic research suggests they may be mutating into a new species
  • The crocs live in the Abanda caves in Gabon.

(CNN)In a pitch black, bat-ridden cave in the central African country of Gabon, scientist Olivier Testa came face to face with a terrifying creature with bright red eyes and orange scales.

"It was maybe two or three meters from me and the eyes were bright red, reflecting my light. I was so frightened," Testa, a cave expert said.
    In the course of his work, Testa has come across many weird and wonderful sightings -- but none as bizarre as this orange reptile with blazing red eyes.
      Testa and his colleague crocodile expert Matt Shirley first visited the site in 2009 after an archeologist named Richard Oslisly spotted the crocodiles in the cave. They have visited the location in an isolated region of Gabon six more times.
      "First we confirmed that there were crocodiles in the cave and when we took one of them outside the cave, it was bright orange. That was amazing," Testa told CNN.
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      Little is known about the mystery crocodiles. However, recent research led by Shirley suggests that they may be evolving into a totally new species.
      The species may be mutating as it has a different genetic haplotype to other African dwarf crocodiles living outside, which means that the reptile is adapting to life in the dark.
      "The crocodile head shapes are much more archaic, brow ridges very marked, and the haplotype is a 1 haplotype found exclusively in the Abanda caves and nowhere else, including just outside," Oslisly told CNN.

      Why are they orange?

      The tropical forest covers 85% of Gabon.
      The tropical forest covers 85% of Gabon.
      Perhaps the most puzzling mystery is the color of the crocodiles.
      They're not certain, but the scientists think it might be because of acidic bleaching.
      "The crocodiles live in liquids -- that's guano (bat feces) -- and it's quite a harsh environment. There's a chemical attack on the skin and it bleaches the skin. But we don't have means to prove that," Testa told CNN.
      Crocodile expert Matt Shirley.
      Crocodile expert Matt Shirley.
      Most African dwarf crocodiles are a grayish tone.
      The first orange crocodile they found was about 1.7 meters and was one of the largest African dwarf crocs Shirley had found.
      Another interesting quirk is that crocodiles often require sunlight to regulate their metabolism. These can survive years in darkness.

      Crocs been Tango'd