0*0* BORN AT NORTH ALLEY BURROW, 1948 
5 • ■ BORN MARCH 16, 1948 
4* ■ BORN MAY 16, 1948 
9 ? BORN AT NORTH ALLEY BURROW, 1948 
2 • • BORN MARCH 16, 1948 
3 • ■ BORN MAY 16, 1948 
Figure 115. — The distribution of captures of rats born on March 16 and May 16, 1948, at the North Alley Burrow. En- 
closed dots or squares represent terminal captures. These records exemplify two principles of distribution following 
birth. The first of these is that males become more widely distributed than do females. Secondly, individuals of both 
sexes of these socially lower ranking rats showed considerably less tendency to invade areas away from their place of 
birth, than did rats born in a more favorable location such as at the South Alley Burrow as shown in figure 114. 
9 o’O’ BORN AT SOUTH ALLEY BURROW AND TILE 
BURROW SUMMER AND FALL OF 1948 
6 s?BORN AT SOUTH ALLEY BURROW AND TILE I 
BURROW SUMMER AND FALL OF 1948 
AREA III 
AREA 
AREA 
AREA II 
Figure 116. — The distribution of captures of rats born at the South Alley Burrow during the summer and fall of 1948. En- 
closed dots or squares represent terminal captures. These rats born at the South Alley Burrow late in the breeding sea- 
son experienced more slress from social interactions than characterized rats born here earlier. As a consequence these 
later born rats, particularly the males, became less widely dispersed, and more confined to area IV, which became a 
place where social outcasts aggregated. Compare with figure 114. 
168 
