How did the extra toes specifically aid the Lundehund in maneuvering across slippery coastal cliffs?

By increasing surface area contact and distributing weight and pressure more effectively

The primary benefit derived from the six functional toes on the Lundehund's paws was enhanced purchase and grip when navigating difficult terrain. Each additional toe acted as an independent anchor point, significantly increasing the total surface area of the paw that contacted the surface. This increased contact allowed the dog to distribute its weight and pressure more efficiently across uneven, slippery surfaces like wet granite or ice formations, effectively equipping the dog with built-in high-traction gear necessary for vertical and horizontal climbing.