Size determines whether or not crocodiles go on the move
Tracking data suggests many estuarial crocs migrate as much as 620 miles over the course of a year.
By Brooks Hays | Sept. 21, 2015 at 2:28 PM

BRISBANE, Australia, Sept. 21 (UPI) -- When crocodiles show up on a public beach or in the middle of a park, it's not ideal.

Part of the job of a wildlife manager is protecting animals (especially dangerous predators) and humans from each other. To do so, biologists need to know what inspires a crocodile to light out for new territory.

It turns out, size has something to do with it.

Since 2008, researchers at the University of Queensland, in Australia, have been tracking the movement of crocodiles. And their data has turned up an interesting correlation.

While smaller crocs tend to hide in creeks and larger crocs mostly reign supreme in local water holes, medium sized crocs tend to migrate.

"We've discovered a strong relationship between crocodile size and how they use the environment," biologist Professor Franklin, who founded the croc-tracking research program at Queensland, said in a recent press release.

"It's middle-size crocs, about 3 to 3.5 metres long, that seem to be nomadic -- and these are the ones causing problems for humans," Franklin explained. "By monitoring their movements we are starting to understand what wildlife managers are seeing on the ground with animals moving outside their normal ranges."

The program currently tracks 139 crocodiles using waterproof devices which relay the reptile location to satellites, which then beam down the coordinates to researchers at Queensland's School of Biological Sciences. The movements of the more well known crocs are shared on the program's website.

Tracking data suggests many estuarial crocs migrate as much as 620 miles over the course of a year.

Researchers are currently installing a new generation of trackers on captured crocs -- trackers that will offer another decade of mineable data.

"We have seven years of data, and with a new generation of acoustic tags set to last 10 years, potentially we'll have 17 years of information -- an unparalleled data set internationally," Franklin said. "Our goal is to understand the role of crocs in the ecosystem and look how they move into the river systems, estuaries, creeks and waterholes."

Franklin and his colleagues are now working on computer models to determine how climate change will affect the movements and preferred stomping grounds of Australia's crocodiles.

http://www.upi.com/Science_News/2015/09/.../8321442855124/