Sri Lanka’s Crocodiles: insights to Marsh and Saltwater Crocodiles

Often referred to as the closest living creature from the period of dinosaurs, crocodiles date back some 230 million years, and have existed virtually unchanged for the past 65 million years. Leading crocodile researcher Dinal Samarasinghe gives us insights in the first of our series covering these ancient reptiles.

Of the 24 species of crocodiles that exist in the world today; only saltwater, or ‘salties’, and marsh or ‘mugger’ crocodiles are found Sri Lanka. Carnivorous creatures, these reptiles are the apex predators in their ecosystem owing to having the most complex of metabolisms, which plays an immensely crucial role in the balance of its ecosystem. Feeding on weak and sick fish; a crocodile’s scavenging nature keeps fish populations under control and water sources clean and uncontaminated.

The differences 

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Saltwater Crocodiles. Pic by Dinal Samarasinghe

The two species are easily distinguished by a few distinct physical traits; saltwater crocodiles feature two ridges begin from the eyes to the nostrils, a feature absent in the mugger crocodile. The presence of two pairs of post occipital scutes are apparent in muggers and absent in the saltie. The color and hide pattern also differ in the two species – salties have a yellow or yellow and black hide showing off oval patterns, while muggers have irregular shapes and stripes but are more uniform in color, a grey-brown that allows them to blend in to their marshy environment. Differences also exist in nesting behavior; a mugger digs a hole to lay eggs whereas salties build a nest using surrounding vegetation. A unique mugger behavior is aestivation: this is where they dig themselves a burrow to survive the harsh dry season.

 FACT: The Saltwater crocodile is the largest living reptile; its hide is the most sought-after crocodile skin in the commercial world.

Habitat

In Sri Lanka, saltwater crocodiles number in the hundreds, while muggers number in thousands (an estimated population of 10,000) and are found across the island. Saltwater crocodiles are generally confined to coast areas, outside of protected national parks but have been studied to travel far up larger river networks. The mugger crocodile is found more widely, spread across dry-zone areas; neither of the species has been sighted higher than 150 meters above sea level. Crocodiles spend most of the time in the water but are not comfortable in waters that are deeper than about 10 meters.

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Marsh or Mugger Crocodiles. Pic by Dinal Samarasinghe.

Behavior

While crocodiles have an overall scary reputation, the temperament between the two species have been known to vary; while muggers have been known to show a lighter temperament due to being more social, the saltie has been known to have a more aggressive temperament owing to its territorial nature. Both crocodiles however, are known to be man-eaters.

….TO BE CONTINUED

 

 

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