The Hispid Cotton Rat's fur is sprinkled or streaked with blackish or dark brownish and grayish hairs. The Rats molt, losing and getting a new coat, three times in three months as they move through juvenile and subadult stages and into adulthood. Learn more about the Sigmodon hispidus, more commonly known as a Hispid Cotton Rat, in this easy-to-read species overview by the Smithsonian's National Museum of Natural History.