noun

• An inner layer of short, fine fur or down underlying an animal's outer fur, providing warmth and waterproofing.

  ‘Beneath the overfur is short underfur of finer texture.’

  More example sentences

  • ‘The fur is composed of short, soft underfur covered by shiny guard hair.’
  • ‘The pelage lacks underfur and is usually some shade of brown.’
  • ‘Another characteristic of aquatic and semiaquatic mammals is that they are often well insulated; beavers accomplish insulation by a pelage that consists of long overfur (guard hairs) and dense underfur.’
  • ‘When you look at fur, especially the really dense fur of mammals, you look at that underfur, and it looks like down.’
  • ‘The fur of sea otters is very dense with an insulating underfur and a layer of long guard hairs over the top which trap a layer of air, adding further to the insulation.’
  • ‘The pelage of cane rats is unusual, made up of coarse, flattened or grooved bristle-like hairs, and lacking underfur.’
  • ‘A reindeer's key defense against the cold is an exceptional winter coat that has a fine underfur combined with long, hollow guard hairs that contain thousands of tiny, insulating air cells.’
  • ‘To the contrary, caribou underfur (like caribou skin in general) is not waterproof or water-repellent: moisture penetrates it easily.’
  • ‘Gray wolves have a dense underfur layer, providing them with excellent insulation against cold conditions.’