- The largest reptiles on the planet, saltwater crocodiles not only live in northern Australia but have made their way to the South Pacific.
- As a result, their entire range also includes Fiji, China, India, the Philippines, Thailand, the Solomon Islands, Sri Lanka, the Sunda Islands, and Vanuatu.
- Their ability to go for up to a year without eating and scales which are impermeable to seawater, enable them to drift with the tide to new regions.
For years, tales of big saltwater crocodiles (salties) swimming far out to sea have persisted. But, until 2010, no one had ever attempted to study the oceangoing habits of salties to determine whether these stories were fact, or fiction. Then, with a study partially funded by the late Steve Irwin (known as The Crocodile Hunter), researchers finally tackled the big question. Namely, whether or not crocodiles can “surf”. And, if they can, just how far they can go.
Here, we’ll learn more about the incredible reptiles that are saltwater crocodiles. We’ll find out what they eat, where they live, and what they look like. Then, we’ll take a look at the 2010 study, and find out whether or not crocodiles really can surf the ocean currents.
All About Saltwater Crocodiles
Saltwater crocodiles are the largest reptiles on the planet. The largest males can top 20 feet, yet, these fearsome predators provide excellent, attentive care to their hatchlings. Salties famously live in northern Australia, but would you believe that they also live throughout much of the South Pacific? That’s right, crocs have found a way to cross oceans in search of new places to live. Let’s take a look at some of the things that make salties so special.
Where Do Saltwater Crocodiles Live?
Saltwater crocodiles are the largest crocodilians alive today. Crocodilians include all crocodiles (including Nile crocodiles) as well as alligators, caimans, and gharials. Salties are found along the northern coast of Australia and as far west as eastern India and Sri Lanka. They’ve colonized all the islands in the Philippine, Solomon, and Sunda island chains. Salties can also be found as far away as Fiji, Vanuatu, Thailand, and southern China.
Despite their broad range, saltwater crocodiles live in very specific types of environments. Crocodiles can “surf”, but they can’t lived in mountains, plains, or even anywhere too far from water. Instead, these apex predators spend their days swimming in mangrove swamps, rivers, and estuaries. Saltwater crocodiles get their name from their love of brackish (low salinity) water.
Size and Appearance
Saltwater crocodiles typically grow to about 20 feet long, but they can reach even greater lengths. The largest saltie ever reliably measured was over 23 feet long! The largest saltwater crocodiles can weigh over 2,000 pounds. However, because of rampant hunting until the enaction of protections in 1970, there are few truly monstrous salties left.
Like all crocodilians, saltwater crocodiles have heavily armored bodies topped with large heads. They have short legs, heavy bodies, and long, powerful tails. Salties spend most of their time in ‘sit and wait’ ambush, despite this, crocodiles can “surf” using river and oceanic currents. Their thick skin and hydrodynamic bodies help them to reach distant islands.
Diet and Behavior
Saltwater crocodiles hatch from eggs. At birth, baby crocodiles are extremely vulnerable. Luckily, they have their mothers to protect them. Small salties eat insects, rodents, small fish, birds, amphibians, and turtles. As they grow, they can kill and eat bigger game. Adult crocodiles are at the top of the food chain; they eat deer, wild boar, monkeys, gibbons, water buffalo, fish, and even dingoes and kangaroos.
Saltwater crocodiles have one of the strongest recorded bite forces on Earth. Their heads are specially designed to clamp onto prey, and never let go. Because crocs can’t chew, they rely on their teeth and jaw strength to hold on to even the largest of prey.
Can Crocodiles “Surf”?
So, after decades of stories of crocodiles swimming far out to sea, a group of researchers finally decided to test the veracity of the claims. Using traps and anesthetic, they implanted a group of adult saltwater crocodiles with tracking devices. Over the course of a year, they recorded all the crocs’ movements.
What they found was astonishing. The researchers discovered that saltwater crocodiles do indeed travel great distances in open ocean water to reach distant islands. They showed that crocodiles can “surf”; one saltie even surfed over 366 miles in 25 days. To accomplish this, crocodiles only swim when the tide is with them. When the tide is against them, they dive deeper, or rest until the tide turns.
Why Do Crocodiles “Surf”?
So, crocodiles can “surf”, but why do they surf? Previous to the study, scientists had long wondered how saltwater crocodiles could have such a broad range, divided by seemingly untraversable deep ocean waters. Typically, when a group of animals from one species moves to a new island home, they speciate, becoming an entirely new species due to genetic isolation.
But, this isn’t the case with crocodiles. Now that scientists know that crocodiles can “surf” long distances, they have an explanation for this lack of speciation. Their conclusion is that crocodiles who have learned to “surf” have been able to colonize a greater range, which makes them genetically more successful. So, part of the saltie’s secret to being successful is in their ability to travel great distances using ocean and riverine currents.
But Wait, Can Crocodiles Go in Salt Water?
It might seem strange, but saltwater crocodiles can indeed survive in full salinity salt water. They need freshwater to drink, but, when they’re out to sea, crocs can actually go a long time without “drinking”. And, because they have low permeability skin, they don’t soak in the salt water the way other animals attempting the same journey would. Additionally, crocodiles can go over a year without feeding, so getting hungry on a long journey isn’t an issue.
Are Saltwater Crocodiles Endangered?
Thanks to conservation efforts that have been ongoing since the 1970s, saltwater crocodiles are no longer in danger of extinction. Crocodiles can “surf”, but they can also be dangerous to humans. Part of the saltie management strategy is to keep large adults away from urban populations. Unfortunately, there are currently over ten species of crocodilian listed as Critically Endangered. Only extreme human effort will keep these species from going extinct in the upcoming decades.
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- , Available here: http://www.iucncsg.org/pages/Conservation-Status.html
- , Available here: https://www.britannica.com/animal/crocodile-order/Natural-history
- , Available here: https://www.nature.com/articles/news.2010.282
- , Available here: https://besjournals.onlinelibrary.wiley.com/doi/10.1111/j.1365-2656.2010.01709.x