RATS BORN IN NORTH ALLEY BURROW SUMMER 
AND FALL OF 1948 
7 Gutter 7 -born at south alley burrow march 
8, 1948 
N AREA III AREA II E 
Figure 113. — Differences in the distribution of captures of two groups of rats. The South Alley Burrow was a place which 
fostered the development of high social rank in comparison with conditions about the North Alley Burrow. Note how 
the males born at the South Alley Burrow became widely dispersed, whereas rats of both sexes born at the North Alley 
Burrow remained near their place of birth. In part, these records exemplify the inverse relationship between social 
status and the ability to invade other areas already inhabited by rats. 
dV BORN AT SOUTH ALLEY BURROW, 1948 
6 ■ = BORN MARCH 16, 1948 
8 • = BORN MAY 18, 1948 
? ? BORN AT SOUTH ALLEY BURROW, 1948 
5 • = BORN MARCH 16. 1948 
8 • * BORN MAY 18, 1948 
N AREA III AREA II E 
Figure 114. — The distribution of captures of rats born on March 16 and May 18, 1948, at the South Alley Burrow. En- 
closed dots or squares represent terminal records. These records exemplify the general tendency of females to remain 
near their home burrows, whereas males become more widely dispersed. 
167 
