Fishermen discovered the pod of almost 50 false killer whales, which are members of the dolphin family, Sunday afternoon on the Caleta Susana beach in the Strait of Magellan, The Santiago Times reported.
The fishermen alerted the navy, which helped them save the 26 whales, which are 18 feet long and can weigh between 2,000 and 4,400 pounds, the newspaper said.
The reason why the pod became stranded was unknown.
"We are thinking of two possibilities. It is probable that the cetaceans were looking for food and followed a school of fish, ending up getting lost, but the other possibility is that some killer whales pursued them. Local fishermen said they had seen some of them in the area that same day," Jorge Sierpe Gallardo, director of the region's National Service of Fishing and Aquaculture, said.
Authorities are now watching the coast in order to prevent another similar grounding incident from happening, the Times said.