Rescuers in Western Australia have been working to save dozens of stranded whales after at least 50 have died.
On Wednesday morning, almost 100 long-finned pilot whales stranded themselves at Cheynes Beach, five hours' drive southeast of Perth.
Volunteers and workers used slings to refloat nearly half of them.
Sadly 51 died.
Vanessa Pirotta, wildlife scientist at Macquarie University, said it's still a mystery why mass strandings happen.
"The fact they were in one area very huddled and doing really interesting behaviours and looking around at times, suggests something else is going on that we just don’t know," she told 7News.
Australia's Parks and Wildlife Service said staff and volunteers were leading the surviving whales into deeper waters.
Vets, marine biologists, and other conservation staff began grouping them before attempting a refloat to improve their survival chances.
They fear another stranding if the whales get isolated from one another.
Pirotta said unusually, there was lots of footage of the pod before the stranding, suggesting disorientation or illness.
Pilot whales often have a "follow-the-leader type mentality" which could be why, she said.
