Understanding the Differences Between Estuarine and Freshwater Crocodiles, An IPB University Expert Explains: One Is Shy, the Other Is More Aggressive

For some people, crocodiles are synonymous with terrifying wild animals. However, not all crocodiles have the same characteristics. In Indonesia, there are at least two types of crocodiles that are most familiar to the public, the estuarine crocodile (Crocodylus porosus) and the freshwater crocodile, also known as the Siamese crocodile (Crocodylus siamensis).

Although they appear similar at first glance, the two have striking differences in terms of habitat, body size, and behavior. Coinciding with World Crocodile Day, observed every June 17th, IPB University expert Prof. Burhanuddin Masyud explains the differences between estuarine crocodiles and freshwater crocodiles.

“Indonesia is one of the countries with high crocodile species diversity. At least five crocodile species have been identified, though some experts suggest the number could be higher,” said Prof Burhanuddin.

Different Habitats, Different Traits
According to Prof Burhanuddin, estuarine crocodiles typically inhabit rivers, estuaries, coastal areas, and brackish waters. This species has a larger body, reaching lengths of 5–7 meters and weighing over one ton. Their snouts are wide and powerful, and they are known as territorial apex predators that pose a potential threat to humans.

“Estuarine crocodiles are active swimmers, adult males are more dominant and aggressive, and they have strong territorial boundaries,” he explained.

Meanwhile, freshwater crocodiles are more commonly found in swamps, rivers, and freshwater lakes far from the influence of the sea. They are smaller in size, generally measuring 1,5–2,5 meters in length, with a slimmer, “V”shaped snout.

“Freshwater crocodiles tend to be calmer, shy, and avoid humans. Aggressive behavior usually occurs when the animal is cornered or defending itself,” he added.

Protected Species
Prof Burhanuddin explained that both estuarine and freshwater crocodiles are protected species in Indonesia. However, their statuses differ. Estuarine crocodiles are classified as “Least Concern” by the International Union for Conservation of Nature (IUCN), while freshwater crocodiles are classified as critically endangered.

He emphasized that conservation organizations, zoos, and breeding centers play a crucial role in maintaining crocodile populations. In addition to serving as a gene pool, breeding programs can also reduce hunting pressure in the wild and support reintroduction programs. 

“The success of breeding programs can serve as a vital support system for crocodile conservation in their natural habitats while also supporting sustainable use,” he said. (Fj) (IAAS/PRP)