was a loud squeal. He ran outside and paused under some limbs
approximately 15 feet from the house, and remained there for 15 minutes
before clipping off an ironweed 12 inches long, which he carried to the
house. He did not enter the house but stopped beneath overhanging sticks
at the edge, eating leaves from the plant. He made another attempt to
enter the house but loud squeals and rustling followed and he returned
to the ironweed plant and was still eating when observations were
halted. In another instance, squeals and rustling indicated that the
occupant and intruder were in combat.

[Illustration: FIG. 2. Diagram illustrating spacing (due to
territoriality or intolerance of the rats) in twelve woodrat houses in a
hedge row extending south from south boundary of the Reservation at the
middle.]

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 per