How Aggressive Are Crocodiles?

By Reptile Encounters/19 February 2014

crocodile

Saltwater crocodiles are the largest species of crocodile on the planet, with average males measuring about 5 metres long and weighing in at about 450 kilograms. However they can grow as long as 7 metres and weigh as much as 1,000 kilograms! You can see why “salties”, as they are often called, dominate both land and water environments.

That is because in addition to being excellent navigators across earth, saltwater crocodiles are also champion swimmers. Some sailors in the past have reported seeing these ferocious reptiles far out at sea, swimming about with animals like whales and sharks. The area where they are most likely found is eastern India, Southeast Asia, and northern Australia.

Saltwater crocodiles are opportunistic when looking for prey. They do not actively hunt their prey, but rather ambush using their amazing stealth. Saltwater crocodiles feed on a variety of prey from small invertebrates, fish, birds and mammals.

Unlike other animals, however, this type of carnivorous behaviour is not taught to these reptiles by older, wiser generations. For years scientists have debated whether predatory animals, such as the saltwater crocodile, are born with aggressive instincts or if they learn it as they grow up in the wild. But one recent study suggests that these ferocious reptiles come out of the womb ready to bare teeth and bite – even if it means biting each other!

In fact, a study at Charles Darwin University in the Northern Territory observed the behaviours of 90 saltwater crocodile hatchlings from their first week of life onward to determine the extent of their combative nature. It tested the hatchlings responses to aggression by gauging the timing, duration, and intensity of each type of interaction used. The researchers also recorded where the interaction took place, such as on land or in water.

The study revealed that baby saltwater crocodiles have the same level of aggressiveness as adults who spend their entire lives in the wild. According to biologist Matthew Brien, who led the research, “The saltwater crocodile has a reputation for being one of the most aggressive species in the world as an adult.”

Some of the aggressive actions, like responding to another hatchling disturbing the sleeping space or violating the personal space of one of their peers, were deemed unintentional. However the interactions that were of higher aggression appeared deliberate due to the more intense physical contact between the hatchlings.

The study revealed that the aggressive interactions adopted a certain posture and approached each other with rapid movements. And the final results showed that all aggressive interactions that took place between the hatchlings took place in open water. None took place on land, or near feeding areas located in land-based environments. This seems logical when taking in account that adult saltwater crocodiles grab their prey and pull them under water until the victim drowns.

Despite the size and aggressive nature of the saltwater crocodile, each day a little more of their habitat is lost to human activity. Because their hides are valued above all other members of the crocodile species, illegal hunting is also putting these impressive reptiles at risk. Perhaps the worst fate facing the saltwater crocodile is the fact that humans have given it a bad reputation as a man-eating beast. While these creatures are currently at a low risk for extinction, without the efforts of wildlife conservation their numbers would plummet until the only way to learn about them would be through articles such as this one.