Homesick crocs shock Australian researchers

Sep 26, 2007, 6:45 GMT

Sydney - When Australian authorities find deadly saltwater crocodiles too close to places where people might swim, they shift them to a habitat a lot more remote, but research released Wednesday suggested the relocation programme might be futile or even counterproductive.

Crocodiles are home-oriented creatures who return to where they come from and shifting them might make them even more cranky and aggressive, it indicated.

'We often thought crocodiles tired very quickly, but here we show very clearly that they are capable of moving long distances for days on end,' University of Queensland biologist Craig Franklin said.

The researchers attached battery-powered transmitters to the heads of three crocs relocated from Darwin harbour in far-northern Australia and then tracked their movements by satellite.

Rather than settle happily in their new habitat, the three relocated reptiles got homesick and returned to where they were caught.

One swam 400 kilometres in 20 days to get back home. Another swam 130 kilometres and a third 52 kilometres.

Professor Franklin said crocodiles probably used the sun, magnetic fields, sight and smell to find their way back home.

'Crocodiles are more closely related to birds than they are any other reptile, so they are possibly using navigation systems similar to birds,' he said.

He also warned that taking crocodiles away from their own patch might make them more aggressive because they became homesick and anxious to return to the place they knew.

The late Steve Irwin was involved in the research. The famed Crocodile Hunter of the eponymous television series caught the crocodiles and helped tag them.

Irwin died in September last year when he was pierced in the heart by a stingray barb he was filming on Australia's east coast.

The crocodile relocation policy has been in place since the 1970s when crocodiles became a protected species and hunting them was forbidden.