An undercoat is a layer of soft, insulating fur found beneath the outer coat of many animals, particularly in dogs and cats. This layer helps regulate body temperature, keeping the animal warm in cold weather and cool in warmer conditions. The undercoat is typically denser and shorter than the outer coat, which consists of longer, protective hairs. In addition to providing insulation, the undercoat can also help with moisture resistance. Animals with a thick undercoat, such as Siberian Huskies or Golden Retrievers, often shed their undercoat seasonally, which is a natural process that helps them adapt to changing climates.