Brush rabbit the drier seasons while grasses are used in the wetter seasons in relation to growth of annual vegetation. Use of habitat also probably is related to the breeding season. The brush rabbit is smaller than many of the other cottontails, and unlike most of them, the underside of its tail is grey rather than white (which may be why its common name does not include the word "cottontail"). The upperside of the brush rabbit's fur varies from light brown to gray in color, while the underside is usually always white. Adult rabbits measure anywhere from 10–14 inches long and rarely
European rabbit naked, have white flesh, and little sexual dimorphism. However, the two differ in skull characteristics, and cottontails do not habitually construct their own burrows as the European rabbit does. Molecular studies confirm that the resemblance between the two is due to convergent evolution, and that the European rabbit's closest relatives are the hispid hare, the riverine rabbit and the Amami rabbit. The oldest known fossils attributed to the modern European rabbit species are around 0.5 Ma old (Middle Pleistocene). , six subspecies are recognised. The European rabbit is smaller than the brown and mountain hare, and lacks black ear-tips, as