An 18-foot (5.4-meter) minke whale ran aground on a sandbar in Brazil's Amazon jungle, some 1,000 miles (1,600 kilometers) from the Atlantic Ocean, Brazilian media reported Friday.
The Globo television agency broadcast images of dozens of people gathered along the Tapajós River splashing water on the animal, whose back and dorsal fin were exposed to the hot Amazon sun.
Sea creatures rarely venture so far into fresh water.
"It apparently got separated from its group and swam upstream," biologist Fabio Luna said in a televised interview from the site. "It's very unusual."
Scientists were working to dislodge the mammal and return it to the ocean. They said it weighed about 12 tons.
The whale beached itself Wednesday near Santarém in Pará state, Brazil's Environmental Protection Agency said, according to the Globo newspaper. Phone calls to the agency were not immediately answered.
The creature reportedly is a minke whale. With an average length of about 23 feet (7 meters), minkes are the second smallest of the baleen whales after the pygmy right whale.
The International Whaling Commission Scientific Committee estimates there are about 184,000 minke whales in the central and northeast Atlantic Ocean.