A humpback whale has found its way back to sea after getting lost in crocodile-infested waters in northern Australia.
The whale was one of three spotted in the remote East Alligator River in the Northern Territory's World Heritage-listed Kakadu National Park earlier this month.
Two swam in the river for a short time before returning to the sea but the third appeared to have become stuck.
It is the first known sighting of humpback whales in the river and it is not clear why they ventured so far inland to shallow, crocodile-infested waters.
Boats were banned from entering part of the river amid fears the remaining humpback could be hit by a vessel or forced further up the river, while Parks Australia officials and NT government scientists were on standby to intervene.
But, to their relief, the whale managed to find its own way out during high tides over the weekend after spending 17 days in the river about 20km (12 miles) upstream.
Dr Carol Palmer, a senior scientist for the state government, said the whale’s escape was “great news”.
She added: “I’m very happy it has found its own way. This is the very best outcome we could have hoped for.”
Dr Palmer said the whale may have “been chased up the river by some big sharks” or “maybe it was just a wrong turn”.
The humpback appeared to be in a good condition when it was spotted by scientists in the Van Diemen Gulf on Sunday.
Kakadu National Park manager Feach Moyle said it was “not suffering any ill effects” of its adventure, adding: "We’re so grateful to Kakadu’s traditional owners, national park staff and scientists from the NT and across the country, who have worked together to manage this very unusual situation for a good outcome.”
Despite the river's name, there are no alligators in Australia.
It was named after the river's many crocodiles by European explorers who apparently could not tell the difference.
Authorities thought the whale was too big to be attacked by crocodiles, unless it became weak or sick.
Additional reporting by AP