The species is an infrequent visitor to the North Sea.
A recovery operation is under way after two whales became stranded off the east coast of Scotland.
The coastguard was alerted around midnight on Monday to a report of two whales beached on the shore in Culross, Fife.
The northern bottlenose whales are understood to be rare visitors to the North Sea.
British Divers Marine Life Rescue (BDMLR) said one of the animals died around 6am on Wednesday and the other is in shallow water, but is unlikely to survive.
South Queensferry coastguard rescue team is assisting.
The animals are thought to be two from a trio of the same species spotted in the Moray Firth earlier.
The stranding is the latest of several in the UK and comes 10 days after a pod of 55 whales beached in the Western Isles.
In autumn 2020, rescuers, including BDMLR, the Ministry of Defence and local volunteers, attempted to shepherd a pod of northern bottlenose whales to sea from Loch Long, Argyll, ahead of a major military exercise.
They switched to monitoring the animals from shore after unsuccessful herding attempts.
