The exact reasons for stranding are unknown, but mammals are very sociable and can follow their fellows into danger.
At least 26 pilot whales have died, but several others have been rescued after 160 of them became stranded across a large area in Western Australia.
Dozens of whales were stuck in shallow water spread over about 500 meters (0.31 miles) at Toby Inlet in Geographe Bay near Dunsborough on Thursday morning. The region is less than 250 km (155 miles) south of the state capital Perth.
Footage from the area showed wildlife rescue teams and local authorities joined by many volunteers to help them return to deeper waters.
Pia Courtis, a spokeswoman for the Ministry of Biodiversity, Conservation and Attractions, said samples would be taken from the deceased whales before they were removed from shores.
More than 100 whales were taken offshore, but Courtis said they could return.
“We have ships on the water and a reconnaissance plane in the air doing searches every few hours to see where they are,” she said.
“So far so good, they didn’t make it back to shore.”
The ministry said that once whales become fully stranded, they typically need to be euthanized as this is “the most humane outcome.”
There are another 20 whales in a pod about 1.5 km offshore. Another group of about 110 animals is closer together offshore. https://t.co/H26PrW3f2o
– Shark Safety WA (@SharkSafetyWA) April 25, 2024
Mass strandings of pilot whales are not uncommon in Australia and New Zealand. But after decades of such events, scientists don’t fully understand why they occur. Some researchers believe that if the pods feed too close to shore, they become off track.
Pilot whales – which can grow up to 6 meters (20 feet) long – are very sociable and can therefore follow their fellow whales when they are in danger.
Some stranding incidents have been linked to human-caused underwater noise pollution, which could affect the animals’ sensitive hearing.
Wildlife experts say the whales’ unusual behavior could also indicate stress or illness within a pod. Pilot whales often maintain close relationships with their groups throughout their lives.
About 500 pilot whales died when they became stranded on New Zealand’s remote Chatham Islands in 2022.
The most recent mass stranding in Western Australia occurred at Cheynes Beach in Albany in July 2023, where at least 90 of the mammals died.
The largest whale beach in Western Australia took place in Dunsborough in 1996 and included 320 pilot whales. All but 20 animals were rescued and returned to deeper waters.
Authorities have asked people not to try to save the whales without the advice of experts, as doing so could cause further injury to the animals, hinder coordinated rescue efforts or harm themselves.