Natural World: Invasion of the Crocodiles (6 of 23)

Invasion of the Crocodiles

By the end of the night, four more crocodiles are tagged in the Mary River.
For the next year, a satellite deep in space will track their exact positions.
Next morning, they head to Kakadu National Park and the second study area, the South Alligator River.
Controversy continues in the Northern Territory over some of Kakadu National Park's top tourism spots.
A record number of saltwater crocodiles are being found in the area.
The vast South Alligator River cuts a path through the heart of Kakadu.
At the end of the dry season, its upstream waters dwindle to a series of pools called billabongs.

As these water holes dry out, birds, fish and crocodiles are drawn together in ever-denser numbers.
For the crocodiles, it makes for easy pickings.
Ten years ago, these billabongs marked the end of the salties' range.
But every year, they are moving further and further up river.
50 kilometres upstream, Jim Jim Falls lies at the source of the South Alligator.
It 's one of Kakadu's most popular swimming holes.
But now crocodiles are moving dangerously close.
As concern mounts over the safety of the falls, Kakadu ranger, Garry Linder, hopes the study will reveal how and when the crocs are moving.
Over the next two weeks, 11 more crocs are tagged in the South Alligator River.