Four sperm whales stranded on a beach in Indonesia have died despite a 24 hour rescue attempt, though volunteers managed to save six others.
The World Wildlife Fund (WWF) said the 10 whales beached themselves on Monday off the coast of Aceh, northern Sumatra.
With the help of the navy and locals, seven of the whales were dragged out to deeper water, but one returned and was stranded again, this time fatally.
Dwi Aryo Tjiptohandono, WWF Indonesia's marine and fisheries campaign coordinator, said the organisation was investigating the stranding and autopsies will be carried out on the corpses.
There are fears the remaining six whales could try and come back for the dead members of their pod, and risk being beached again, he added.
According to Whale Stranding Indonesia, there have been at least 41 recorded strandings of animals in the country before this latest incident.
Scientists still do not know why whales beach themselves, though a factor is thought to be the creatures' strong social bonds.
When one or two initially beach, they send out distress signals that can trigger other members of the pod to try to help. This can then set off a chain reaction where more and more become stranded.
In February around 400 pilot whales died in New Zealand after one of the worst beaching events in the country’s history.
