Although home ranges may overlap to some extent, intraspecific intolerance tends to maintain a certain minimum interval between houses. The arrangement of twelve houses along a hedge row 1170 feet long is diagrammatically represented in Figure 2. The average interval was 78.5 feet (minimum 42; maximum 171). The habitat was uniform. Home ranges probably overlap somewhat, and the spacing is the expression of the need for an otherwise unoccupied area in which there is sufficient space to live. Because individuals tend to fight whenever they meet, there is probably a psychological tendency for sequestration which results in spacing of houses and reduces social contact thereby avoiding a depletion of energy that would be detrimental to the population. Whereas condition of the hedge row determines whether or not it will be inhabited by woodrats, length determines the number of occupants. The spacing of houses in a hedge row must be attributed to something other than restriction of sites because the number of sites available always exceeds the number that are in use. Although rock outcrops situated in areas of uniform habitat have not been observed to the extent that hedge rows have, a similar spacing seems to exist and the sites available for houses always exceed the actual number found. This behavior pattern limits the number of houses and is probably advantageous to the species through preventing overcrowding and possible critical depletion of the food supply. Eleven of the young that weighed 100 grams or less when originally captured and were presumably still living at the mothers' houses, were recaptured repeatedly over periods of weeks or months, providing a limited amount of information regarding dispersal. They followed no definite pattern. In seven instances (five males and two females) the young stayed on at the house beyond the age when they were completely independent of the female. In at least two instances the female was known to have moved away while the young remained. One female shifted to a house 58 feet from the one where she had reared her litter of two, and was accompanied by the young male, while the young female stayed on in possession of the maternal house. Two months later this young female was caught at a house 90 feet away, and an adult male was in possession of her former house. One young male shifted to a house 220 feet from his original home and remained there several months, but was recaptured once back at the original location. Another male made a series of moves over a period of weeks and finally settled in a house 490 feet from his first home. One male who stayed in the maternal house all summer, and reached adult size there, later moved several times, and was last recorded 900 feet away. One young female shifted 110 feet. In several instances juveniles appeared abruptly in houses known to have been unoccupied previously, and some of these houses were in poor repair. These young