Homing Crocs
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Saltwater crocodiles are making marathon ocean swims to reach home even if they are airlifted hundreds of kilometres away, new research shows.
Three airlifted crocodiles in Far North Queensland have been tracked swimming between 10 and 30 kilometres per day with one crocodile swimming around the northern tip of Australia to reach home – covering more than 400 kilometres in 20 days. The results are from the first satellite tracking study of wild crocodiles undertaken by UQ, Australia Zoo and the late Crocodile Hunter, Steve Irwin, and Queensland Parks and Wildlife Service. Using satellite telemetry, the team found crocodiles had remarkable homing and navigational skills and stamina to swim large open water voyages. All three monitored crocodiles were moved by helicopter between 52 and 130 kilometres away but still found their way back to their capture sites. One crocodile was flown across Cape York Peninsula from the west to east coast and then circumnavigated the peninsula to return home.
Project researcher, Professor Craig Franklin, from the University’s School of Integrative Biology, said the data showed crocodiles were indeed oceanic animals which could move phenomenal distances. “We often thought crocodiles tired very quickly but here we show very clearly that they are capable of moving marathon distances for days on end,” Professor Franklin said.
Crocodiles were tracked using a specially designed transmitter attached to the backs of their necks that collected data and relayed it via the ARGOS satellite system back to the scientists.
Professor Franklin said the study showed moving problem crocodiles away to remote river systems was not effective. “Moving crocodiles to isolated waterholes which are surrounded by land might prove to be an effective impediment to them returning home,” he said. He said the results also proved the success of satellite tracking for crocodiles allowing continuous tracking without human interference.
“Steve Irwin was a major driving force behind the study, and his intellectual and logistical support complemented the knowledge, experience and contributions made by the other team members,” Professor Franklin said. “He also gave us the assistance of the croc team from Australia Zoo who are highly skilled in the capture and care of crocodiles.” Professor Franklin said crocodiles probably used many factors such as their position to the sun, magnetic fields, sight and smell to navigate.
 ROAMING reptiles ... Professor Craig Franklin helps capture a crocodile with Australia Zoo staff Photos: courtesy Professor Craig Franklin |
Story author: Miguel Holland
- FUNDING: ARC Linkage Projects Grant, The University of Queensland, Australia Zoo, and Queensland Parks and Wildlife Service (QPWS)
- RESEARCHER: Professor Craig Franklin
- EMAIL: c.franklin@uq.edu.au
- WEB: www.uq.edu.au/eco-lab
