The Merriam's kangaroo rat has a medium-sized, elongated body covered with silky fur, predominantly sandy-brown, interspersed with black and white markings. It possesses long hind legs designed for jumping, short forelimbs ideal for digging and a bushy tail extending its length. The species' large, nocturnally-adapted eyes and prominent ears are notable. There are no significant appearance differences due to age, gender or subspecies.