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.

Dead whales beached on the North Sea coast Show all 8 1 /8 Dead whales beached on the North Sea coast Dead whales beached on the North Sea coast Two dead sperm whales are seen washed up on a beach near Skegness in northeast England. Four sperm whales believed to be from the same pod washed up on beaches in northeast England. Three whales were found on a beach near Skegness and one died on Hunstanton beach AFP Getty Dead whales beached on the North Sea coast 50ft sperm whale beached in Norfolk The dead 50ft (14.5m) young adult male sperm whale beached in Norfolk, which was was part of a group of six spotted in the Wash at Hunstanton, is believed to have been part of a pod that stranded and died in the Netherlands PA Dead whales beached on the North Sea coast 50ft sperm whale beached in Norfolk The dead 50ft (14.5m) young adult male sperm whale beached in Norfolk, which was was part of a group of six spotted in the Wash at Hunstanton, is believed to have been part of a pod that stranded and died in the Netherlands PA Dead whales beached on the North Sea coast 50ft sperm whale beached in Norfolk The dead 50ft (14.5m) young adult male sperm whale beached in Norfolk, which was was part of a group of six spotted in the Wash at Hunstanton, is believed to have been part of a pod that stranded and died in the Netherlands PA Dead whales beached on the North Sea coast 50ft sperm whale beached in Norfolk The dead 50ft (14.5m) young adult male sperm whale beached in Norfolk, which was was part of a group of six spotted in the Wash at Hunstanton, is believed to have been part of a pod that stranded and died in the Netherlands PA Dead whales beached on the North Sea coast 50ft sperm whale beached in Norfolk Two of three dead sperm whales that have washed up on a beach in Lincolnshire, just a day after another was beached in Norfolk PA Dead whales beached on the North Sea coast One of three dead sperm whales that have washed up on a beach in Lincolnshire, just a day after another was beached in Norfolk PA Dead whales beached on the North Sea coast Photo taken from the Twitter feed of the @RNLIskegness of one of three dead sperm whales that have washed up on a beach in Lincolnshire, just a day after another was beached in Norfolk PA

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.