These Fascinating Orange Dwarf Crocodiles May Be Evolving Into A New Species
Though animals are continually evolving to adapt to their environment, it is hard to observe the process real time in the wild. Now, some international scientists have stumbled upon a unique group of West African dwarf crocodiles that may be in the midst of mutating into a new species.
The reptiles were first discovered in 2008 by Dr. Oslisly, an archeologist, who ventured into Gabon’s remote Abanda caverns in search of African artifacts. Instead, he stumbled upon a group of crocodilians living in a dark room filled with water. Curious to know more, he returned two years later – this time with cave scientist Olivier Testa and crocodile specialist Matthew Shirley in tow. When the team took a captured specimen outside the dark caverns, they noticed that it sported a bright orange exterior – something that has never been observed in the normally bluish-gray reptiles. Subsequent visits to this remote region, which can only be accessed by boat and requires an overnight stay in the forest, revealed thirty more crocodiles, ten of which were bright orange!
The researchers believe that while the younger inhabitants are able to easily move in and out of the intricate maze of caves, the bigger, older crocodiles have a harder time. They theorize that the concentration of bat droppings in the water, where the older reptiles spend most of their day, act as a bleaching agent, causing their gray skin to turn orange. However, thanks to the abundant supply of bats, crickets, and other cave critters, the imprisoned crocodiles are broader and healthier than their forest counterparts, who depend on fish and crustaceans.
While the crocodile’s external appearance and dietary habits were certainly intriguing, what was even more so was the DNA analysis, which suggests that they may be mutating into a different species from their forest relatives. The scientists came to this conclusion after noticing a haplotype – set of genes from one of their parents – that was present in the cave crocodiles but not in their forest cousins.
This discovery has led the researchers to ponder about the crocodiles’. Normally, forest-dwelling African dwarf crocodiles hide their eggs under a mound of fresh and rotting plant material. However, that is non-existent inside the caves. While the younger ones are able to venture outside to breed, the experts are not sure what happens as they grow in size. The two possibilities are that the reptiles either stop breeding or that they leave the caves during the breeding season – this means they may be just seasonal visitors to the cave.
As to why the reptiles frequent the caves in the first place? The scientists speculate it is probably the steady supply of food and to keep safe from their biggest predator – humans. The ferocious West African reptiles, who are currently on the endangered species list, are incessantly hunted by residents for their meat. Oslisly, who is now working to protect the orange mutating crocodiles by turning the area into a wildlife sanctuary, says the only reason they have survived is “because [the] local people are afraid to enter the caves.”
Resources: guardian.co.uk, newsscientist.com,cnn.com.
Reading Comprehension (12 questions)
- What is happening to a group of West African dwarf crocodiles?
- Why did Dr. Oslisly visit the caves where the crocodiles were discovered?
Critical Thinking Challenge
What would you name the new crocodile species? Why is the name...
Vocabulary in Context
“As to why the reptiles frequent the caves in the first place?”
In the above sentence, the word frequent most likely means:
(a) to visit often
(b) located at...