In 1918, the Morro Bay kangaroo rat (Dipodomys heermanni morroensis) occupied one area that contained approximately 35,000 animals. In 1986, the population consisted of only 50 individuals occupying a fraction of the original range. On October 13, 1970, the Morro Bay kangaroo rat was designated as Endangered in the Entire Range. The Morro Bay kangaroo rat, is found exclusively in the state of California. The northern boundary of the species can be defined by a line connecting Suisun Bay to Lake Tahoe. The range extends south for roughly 500 kilometers to Point Conception in Santa Barbara Co. "While found in a variety of habitats, Morro Bay kangaroo rat is limited to elevations of 3000 feet and below" (1 Williams ).
The Morro Bay kangaroo rat ranges in size from 250 to 313 mm in length, with the tail averaging 180 mm in length. This kangaroo rat, like all species of kangaroo rats, has long hind legs, small front legs and feet, brown upper parts, and a white belly. It is considered to be the darkest in color of all kangaroo rats. The lack of a complete hip stripe distinguishes this animal from other kangaroo rats. The hip stripe is conspicuously absent in this subspecies. .
Morro Bay kangaroo rat breeds from February to October. Breeding peaks in April. "The gestation period lasts 31 days, with litters of up to 6 pups being produced. Average litter size has been reported to range from 2.6 to 3.7." (2 W. Thomas & Betsy Bush Jones) The newborn kangaroo rat is mostly hairless, and the eyes and outer ears are closed. The cheek pouches at this stage are simple folds. By day 3, the young rat is able to crawl and begins to grow hairs. It has skin pigmentation that matches adult patterns. By day 9, the sex of the rat can be determined by checking for swellings in the genital area (swellings are present in males, absent in females). By day 14 the kangaroo rat pup can stand, and the weaning process begins in the third week and is completed by day 25.