Some animals have hair composed of solid tubular strands, while others have hollow, air-filled tubes?

Question

Some animals have hair which is composed of solid tubular strands, while others have hollow, air-filled tubes. Where would one more likely find the latter animal: In cold climates, or warm?

Answer 1

the latter would typically be found in colder climates as the hollow tubed hairs act as insulation- like coats filled with fiberfill or down, the trapped air in the hairs warms better than solid hairs

Answer 2

By definition, there can be no solid, tubular strands. Tubular is hollow and air-filled, while solid is, well, solid