While salt-water crocodiles are the largest living reptiles in the world, they have very little stamina when it comes to swimming. Even a 20-minute swim is work for these ferocious animals - Yet, they seem to make their way all across the seas. Now scientists may have finally solved the mystery of how they do it - They surf!
It seems the crocs know how to hitch a free ride across hundreds of miles by catching on to ocean currents. What is even more amazing is that the crocodiles know exactly what currents to take, depending on their destination. If the currents were headed in a different direction, they simply hung around until things changed.
The findings were released by Australian ecologist, Hamish Campbell and a team of government rangers, who have been observing 27 adult crocodiles that reside in Queensland's Kennedy River, for the last six years.
The scientists tagged the crocodiles and followed their movements with underwater receivers and sonar transmitters. Over the six years, they observed a number of interesting things.
Eight of the tagged crocodiles, who normally had a hard time swimming for 20 minutes at a stretch, had somehow managed to make several trips, back and forth from the estuary to the sea, a distance of almost 35 miles.
Suspecting that the reptiles were not really swimming all the way, the scientists observed the current patterns in the ocean, and found what they were looking for. Years of living on the seashore have made crocs quite astute about knowing what current to catch and ride, for miles on end.
What was even more amazing was how accurate their sense of direction was. One of them left the mouth of the Kennedy River and made his way to the West Coast of the Cape York Peninsula, a distance of 590km, which he managed to get to, in 25 days. To get there the smart crocodile had to catch a particular current that only occurs seasonally, during the summer months.
Yet another smart croc decided to head from the East Coast of the Cape Peninsula through the Torres Strait, to the Wenlock River that lies on the west coast of Cape York, a distance of 411km. When he arrived about halfway to the Torres Strait, the currents shifted to the opposite side of his final destination. Realizing this, the crocodile just hung out for a few days and continued his journey, when the currents changed direction.
Since the reptiles can survive without food or fresh water for many months, they are able to undertake long journeys and can wait for indefinite periods of time, for the right currents to come along.
The findings not only helps scientists understand how the estuarine crocodiles have migrated around the South Pacific, but also, how crocodiles have managed to travel through vast stretches of water in the past.