More than a dozen pilot whales were euthanized on humanitarian grounds. The Scottish Marine Animal Stranding Scheme (SMASS) is investigating why the whales got stranded|Instagram

A pod of 55 pilot whales died after being stranded on a Scotland beach Sunday as rescuers’ attempts to refloat the whales failed due to their size and weight.

Coast guard officials were able to refloat one whale successfully.

More than a dozen pilot whales were euthanized on humanitarian grounds. The Scottish Marine Animal Stranding Scheme is investigating why the whales got stranded.

It was one of the largest fatal mass stranding events in decades, says British Divers Marine Life Rescue director Dan Jarvis.

He also added, “Pilot whales have strong social and emotional bonds with each other,” and, “If one of the whales is in difficulty and becomes stranded, the rest will follow and end up stranded.”