88 
Psyche 
[June 
and has a much smoother surface (fig. 5), but there is no reason to 
believe that it contains any material different or more selected than 
the adult food ball. All the extra care appears to go into the sur- 
face layer. The brood ball measures 20 — 22 mm in diameter ( 10) . 
Rolling and burial. Unlike the food ball, which once shaped is 
rolled off more or less without interruption, the brood ball is often 
shaped several times during pauses in the rolling process. Shaping, 
as previously stated, is a cooperative act of the sexes and the female 
will often be seen continuing shaping even while the ball is being 
rolled. It is the male exclusively who rolls (17), the female merely 
walking head upward over the forward surface of the ball in time 
with its rotation, as on a tread mill (fig. 5). She does not help in the 
rolling process in any way that I could see, except perhaps as a 
counterweight. On the contrary, when the male has temporarily 
lost the ball after a tumble or is fighting off an attacker, the female 
will sometimes make off with the ball herself (3). In the three such 
cases observed the male soon caught up with the female rolling the 
ball and displaced her in the rolling position, whereupon the female 
climbed back onto the ball. 
Table I. Data on dung balls made by Canthon pilularius (L.) 
FOOD BALLS 
BROOD BALLS 
Range 
Average 
N 
Range 
Average 
N 
Time for 
making ball (min) 
12-20 
15.1 
12 
>20-35 
— 
8 
Size of ball (mm) 
15-23 X 17-30 
19.8 X 22.9 
11 
20-22 X 20-22 
20.7 X 20.7 
10 
Time rolled (min) 
2-18 
9.5 
16 
3-23 
9.3 
10 
Distance rolled 
(cm) 
15-830 
267 
19 
90-1060 
414 
14 
Depth buried (cm) 
1.5-4 
2.6 
9 
6-10 
7.6 
9 
The actual rolling process is the same as that described for the 
food ball. During the orientation pauses after a tumble, when the 
male roller climbs onto the ball, he comes into contact with the female 
but no longer displays $ny hostility toward her. 
The distances that brood balls are rolled vary from 90 to 1,060 cm, 
averaging 414 cm (14), and are thus somewhat more than the dis- 
tances recorded for the food balls, although the time spent rolling 
seems to average the same ( table I ) . 
The burying process is the same as that described for the food 
ball. The male does all the work, the female clinging passively to 
