Saltwater crocodiles ride ocean currents to cover large distances.
Credit: Wikimedia
LONDON: Saltwater crocodiles - the world's biggest - ride ocean currents for hundreds of kilometres, effectively surfing to places way beyond its reach merely by swimming, a new study says.
Scientists were at a loss to explain how the estuarine or saltwater crocodile - or "salties" as they're known in Australia - can be found across numerous South Pacific islands separated by huge expanses of water.
So the experts, including the late Australian television nature show presenter Steve Irwin, attached sonar transmitters to 27 adult specimens of the croc (Crocodylus porosus) – with names such as Greg Norman or Nicky-one-eye – to see exactly how they did it.
Riding surface currents
"The study demonstrates that C. porosus dramatically increase their travel potential by riding surface currents, providing an effective dispersal strategy for this species," added the researchers.
Specifically, the crocs - the world's largest living reptile - stayed near the surface when currents there were in the right direction, but dived deeper if flow direction became unfavourable."
The crocodile species can grow up to 20 feet (6.1 metres) in length. One 12.5 foot male travelled some 590 kilometres (367 miles) in 25 days, timing its journey to coincide with seasonal currents.
Covered over 400 km in 20 days
Another 16-footer covered more than 411 kilometres (255 miles) in just 20 days. Again, the crocodile utilised fast-moving ocean currents to reach its destination.
Hamish Campbell of the University of Queensland, said the C. posorus live in islands throughout the Indian and Pacific ocean.
"Because these crocodiles are poor swimmers, it is unlikely that they swim across vast tracts of ocean," he said of the study, published in Britain's Journal of Animal Ecology.
"But they can survive for long periods in salt-water without eating or drinking, so by only travelling when surface currents are favourable, they would be able to move long distances by sea.
"This not only helps to explains how estuarine crocodiles move between oceanic islands, but also contributes to the theory that crocodilians have crossed major marine barriers during their evolutionary past."
wicked
coolest man eater around, imagine seeing a 16 foot crocodile wade its way out of the water onto your little honey moon island, in the middle of the ocean.