Despite unprecedented advancement in science, technology, and innovation, nature holds some of its mysteries inside the fold and when they are out in the open – we are left in awe.
This article aims to shed light on one of those astonishments!
The curious case of cave crocodiles!
The Abanda Caves are a cave complex in Gabon, located in the upstream of Fernan Vaz Lagoon. First mentioned by Dr. Marco Marti and Claude Werotte in the early 2000s, these caves were fully explored during several caving expeditions by Oslisly, Testa, Sebag, and Shirley. Deep within these caves of Gabon, lies a remarkable discovery that speaks for the incredible adaptability of nature.
A unique species of dwarf crocodile, trapped in underground caverns for millennia, has evolved distinctive traits that set it apart from its surface-dwelling relatives.
The discovery of cave crocodiles:
In 2008, archaeologist Richard Oslisly stumbled upon an extraordinary sight in the Abanda caves of Gabon. Hidden in the darkness, a population of dwarf crocodiles had made these damp, isolated chambers their home. These reptiles, believed to have been isolated for approximately 3,000 years, have undergone remarkable changes to survive in their unique habitat.
Unlike their forest-dwelling cousins, these cave-dwelling crocodiles have adapted to a life without sunlight. This adaptation is particularly noteworthy, as most crocodiles rely on sunlight to regulate their metabolism. The ability of these cave dwellers to thrive in perpetual darkness showcases the extraordinary plasticity of life.
Interestingly, this adaptation to cave life mirrors the resilience seen in other species facing challenging environments.
How are they different from forest-dwelling crocodiles?
The cave-dwelling crocodiles were only studied for the first time in 2010, and a 2016 study that compared them to their forest-dwelling counterparts showed several differences between the two. Their diets are very different, with the cave crocs feeding almost exclusively on the bounty of crickets and bats that cling to the cave walls.
They found the cave crocodiles were generally in better condition than those living in the forest, which, as per the team, is likely due to the abundance of prey available and a lack of predators. They suggest the cave crocodiles lay their eggs at the mouth of the caves, then the juveniles venture into the darkness. Once they reach adulthood, it’s thought they barely leave the caves again.
Why ‘orange’?
As per lead author Matthew Shirley, a conservation biologist from Florida International University, who told National Geographic in 2018, the unusual orange skin seen on adult crocodiles may be the result of their time swimming in bat guano, which is rich in urea. Over time, the study authors wrote, this exposure appears to cause chemical bleaching of the crocodiles’ skin.
What do they eat?
One of the most striking and interesting adaptations of these cave-dwelling crocodiles is their diet. While living inside the caves and being unable to access their usual prey, these crocs switched from fish to a menu consisting primarily of bats and crickets. This dietary shift highlights the crocodiles’ ability to adapt their hunting and feeding behaviors to their new environment.
The genetical evolution:
Genetic analysis of these crocs holds even more surprises.
Blood samples from 30 to 40 specimens showed that these cave crocodiles have developed a distinct genetic makeup compared to their surface-dwelling relatives. This genetic divergence suggests that isolation has led to the evolution of unique traits suited to their subterranean lifestyle.
Intriguingly, according to a Guardian article in 2018, this genetic analysis suggests the orange cave crocodiles may be mutating. Researchers told The Guardian that one haplotype (a group of DNA variants inherited from a parent) found in the cave crocs wasn’t present in the forest crocodiles. Study co-author Richard Oslisly, a researcher at France’s Institute of Research for Development, told the Guardian, “The [crocodiles in the] caves of Abanda stand out as an isolated genetic group.”
This genetic change is evidence that the cave crocodiles are evolving into a new species. As per Shirley, who told National Geographic, “As a result of that isolation and the fact that few individuals come in or go out, they’re in the process of [becoming] a new species. Whether that happens soon or not is anyone’s guess.”
Key facts:
Name: Cave-dwelling dwarf crocodiles (Osteolaemus tetraspis)
Where it lives: Abanda cave system, Ogooue-Maritime Province, Gabon
What it eats: Cave crickets and bats
Why it’s awesome: Deep inside one of Gabon’s cave systems lives an unusual population of orange dwarf crocodiles. They live in complete darkness, feast on bats, and swim in liquid guano (aka bat poop.)
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