shelters as at the hopper itself. With many rats 
this “transportation-to-shelter-for-consumption” 
behavior evolved into a “transportation-for-stor- 
age” behavior in which piles of food were left in 
the recorder tunnel. Such food caches were usually 
ignored by the rat which assembled them, al- 
though they then became a secondary source of 
food for rats subsequently coming to the Food Pen. 
Even though most rats engaged in this type of 
shelter storage of food, this behavior became ac- 
centuated among socially low-ranking rats to the 
point that it formed a typical segment of a syn- 
drome of abnormal behavior (p. 196). 
A typical record: Female 7; 324 days of age; 
October 3, 1947; 2:19 to 2:45 p.m. She made 23 
trips carrying garbage into the recorder tunnel 
at Passage 6. During the 12% hours of light suf- 
ficient for observation, 10 other rats made 31 
storage trips into the recorder shelters, 4 trips for 
eating in these shelters, and only 5 trips of storage 
into harborages. 
To a lesser extent caches of food were formed 
under the protective cover of the small trees and 
other vegetation just outside the Food Pen in the 
alleys. Such food caches were used by other rats 
as well as by the one which did the transporting 
to that site. This food might be eaten at this 
location or transported elsewhere. Occasionally 
food was dropped just outside the Food Pen with- 
out any reference to shelter. This abandonment 
of food being transported was at times the result of 
the rat being pursued by another, but at other 
times the food was abandoned for no apparent 
reason that the observer was able to detect. 
There is a characteristic series of developmental 
stages in the maturation of storage behavior to the 
point where food particles are transported over 
the greater distance to the burrow or harborage 
box. These stages are: 
a. Food is eaten directly at the source. 
b. Food is transported into a recorder shelter at 
the entrance to the Food Pen, or into the 
shrubbery just outside the Food Pen where it 
is then eaten. 
c. Food is transported and deposited into 
discrete piles or caches in the recorder shelters 
or in the vegetation just outside the Food Pen. 
d. Food is transported and deposited into 
discrete piles or caches in and at the greater 
distances at which the harborages were 
located. 
There is considerable evidence that a rat in 
motion while transporting a particle of food is 
attracted into the first harborage it passes unless 
the presence of some other rat prevents its entry. 
In my notes there are records of 21 rats making 68 
trips from the Food Pen with food into harborages 
boxes whose positions were recorded (see table 18). 
0.74 of the trips terminated in the two boxes nearest 
the passages through the barrier fence (i.e., box 
positions A and A 1 , see fig. 74). 0.25 terminated in 
the four boxes (B, B 1 , C, C 1 ) which required that 
the rats at least pass by one other box (i.e., A or A 1 ). 
However, only 0.015 of the trips terminated in the 
three boxes (D, E, F), which required that the rats 
pass by at least two other boxes. 
Table 18. — Proportionate distribution of objects or acts 
through the areas 
Position of 
box 1 
389 
rats 
3969 
feces 
4272 
food 
pellets 
68 
enterings 
with food 
A 
.075 
.083 
.029 
. 324 
B 
. 105 
.098 
. 012 
. 015 
G 
. 085 
.075 
. 014 
. 074 
D 
. 175 
. 121 
. 084 
. 000 
E 
. 067 
. 107 
.001 
. 000 
F 
.072 
. 167 
. 017 
. 015 
A 1 
. 123 
. 124 
. 220 
. 412 
B 1 
. 157 
. 074 
. 609 
. 132 
C 1 
. 141 
. 156 
.015 
.029 
A+B+C 
. 265 
.256 
.055 
. 413 
A'+B^C 1 
. 421 
. 354 
. 844 
. 573 
1 See fig. 74. 
On the night of September 14-15, 1948 six 
box traps were left unset and prebaited with 
sunflower seed about each of the Passages 1 to 4, 
through the median barrier fence. No other 
prebaited traps were present in the areas. By 
the next morning most of the seed had been 
removed from all of the traps. All the harborage 
boxes were opened to determine where they had 
been transported. Hulls from the seeds were 
only found in harborage boxes 1, 5, 13, 19, 23, 
and 32. Except for box 13, these represent the 
nearest box that the rats would encounter in the 
process of transporting the sunflower seed to a 
sheltered place to eat. Actually box 13 was not 
an exception since the nearer box 14 was unavail- 
able, since it was filled with a huge colony of 
Formica exsectoides ants. There were many other 
records which showed that food from prebaited 
103 
