Humpback whale is free after swimming out of crocodile-infested river in Australia

A humpback whale has swum free from a crocodile-infested river in Australia, after being stranded there for two weeks, authorities announced on Monday.

It all began when three humpback whales entered East Alligator River in Kakadu National Park. They were spotted last Tuesday, a week after having entered the river, said a spokeswoman for the park, located in Australia’s Northern Territory.

The other two whales were thought to have left the area – but one whale appeared to have gotten stuck in the river, home to a large number of saltwater crocodiles.

A photo of the humpback whale, which swam out of the crocodile-infested river in Australia, posted on September 21.

“After monitoring the whale this weekend, we’re delighted to see it has made its way out of Kakadu’s East Alligator River and into Van Diemen Gulf,” said Feach Moyle, manager of the park’s Country and Culture Section, in a statement on Monday.

“The whale made its way out on the high tides of this weekend and we’re pleased it appeared to be in good condition and not suffering any ill effects,” Moyle added, thanking authorities on state, local and indigenous levels for collaborating on “this very unusual situation.”

Dr. Carol Palmer, a senior scientist for the state government, called the whale’s escape “great news.”

“It’s been fantastic working with staff at Kakadu as well as expert scientists to identify ways to assist the whale, but I’m very happy it has found its own way,” Palmer said in the park’s statement. “This is the very best outcome we could have hoped for.”

An exclusion zone was put in place in Kakadu National Park, after three humpback whales entered the East Alligator River in Australia's Northern Territory.

The whale had apparently gotten stranded after becoming confused during migration, said the national park. “As far as we’re aware, this is the first time this has happened,” it said in a statement last week.

The park said it had been concerned about a number of dangers – apart from the crocodiles, there was also the possibility of a boat colliding with the whale or inadvertently pushing it further up the river.

However, the park added last week, the whale did not appear to be in distress.

Saltwater crocodiles are ambush predators that have been known to attack and kill humans. Despite their name, they can also be found more than 100 miles (161 kilometers) up river from the coast in freshwater habitats.

According to the park’s guidelines to visitors, the crocodiles can stay hidden under water for long periods and can move with great stealth and camouflage. They are quick-acting and have been known to move at speeds of up to 40 feet (12.1 meters) per second when capturing prey over short distances.

Every year between April and November, Australia’s eastern coastline is full of migrating humpback whales; the animals spend their summers feeding in Antarctic waters, before migrating to sub-tropical waters to mate and give birth. The majority of humpbacks near Australia migrate back down towards the Southern ocean from September to November, according to Australia’s environmental ministry.

Australia’s largest national park, Kakadu is dual-listed on the The United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage List for its outstanding natural and cultural values, according to the park’s website.

CNN’s Lianne Kolirin contributed to this report.