The ground colour of Siberian tigers' pelage is often very pale, especially in winter coat. However, variations within populations may be considerable. Individual variation is also found in form, length, and partly in colour, of the dark stripes, which have been described as being dark brown rather than black.The fur of the Siberian tiger is moderately thick, coarse and sparse compared to that of other felids living in the former Soviet Union. Compared to the extinct westernmost populations, the Siberian tiger's summer and winter coats contrast sharply with other subspecies. Generally, the coat of western populations was brighter and more uniform than that of the Far Eastern populations. The summer coat is coarse, while the winter coat is denser, longer, softer, and silkier. The winter fur often appears quite shaggy on the trunk and is markedly longer on the head, almost covering the ears. Siberian and Caspian tigers had the thickest fur amongst tigers.