PICTURES: Assnyt Mountain Rescue team simulate rescue operation in 'spectacular' Bone Caves
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Rescuers have carried out a major exercise in some of Britain's most mysterious and longest caves.
Over several hours - often in darkness and narrow passageways only just large enough to squeeze through - members of Assynt Mountain Rescue Team simulated the difficulties of rescuing a caver.
The operation on Saturday saw 15 members involved at the Bone Caves network in Sutherland.
"With some of the largest cave networks in Scotland it is important to familiarise our team members with the challenges of working underground," said Tim Hamlet, leader of Assynt MRT .
"In the event of an emergency underground, Assynt MRT would support Scottish Cave Rescue Organisation in above and below ground rescue management.
"The caves have become increasingly popular with cavers. We would ask that they make sure their head torch works and have spare batteries, particularly at this time of year.
"The caves go back nearly a mile. They are amazingly spectacular.
"They can get flooded in some parts. We are ready to carry out a cave rescue, but the weekend helped make us even better prepared."
The caves complex near Inchnadamph are where the remains of the only known wild polar bear in Britain were found.
The Bone Caves are popular with hillwalkers and also scientists because of the discoveries made at the site in the past of prehistoric remains of animals, including bears, and humans.
A polar bear skull excavated from one of the caves is the only known remains of the species in Britain. It probably dates to about 18,000 years ago when massive ice sheets covered much of the country at the height of the last ice age.
The creature's bones were first unearthed in 1927 but it was only when the remains were re-evaluated that scientists realised that they once belonged to a polar bear that lived at a time when the climate in Britain was in the grip of a deep freeze.
