1963] 
Matthews — Behavior of Canthon 
89 
the ball and being buried with it. As the ball begins to disappear 
below the surface the female will dig down beneath it, presumably 
to ensure that she will not be left at the surface. The brood ball 
is buried 6 — 10 cm below the surface (9) , two or three times as deep 
as the food ball. Subsequent activity underground is discussed below. 
Since the encounter of the sexes is a chance one, there are many 
instances when the male, having completed a brood ball, is not joined 
by any female. In this case, he will roll the ball off anyway and 
bury it (8). One such ball was dug up 18 hrs later and wasf found 
intact, with the male next to it. This suggests that the beetle stays 
with the ball for a time without eating it, and then perhaps abandons 
it. Abandoned brood balls are not rare in a pasture. 
Robbery and combat. Few attempts at ball robbery are observed 
during feeding activity later in the season, but during mating activity 
in the spring such attempts are extremely frequent and ball makers are 
under constant attack. In all instances checked (21), the attackers 
were males and the defenders also males. Since the female apparently 
never initiates ball making on her own, but joins a male already busy, 
she does not have to defend any balls and is not involved in combat. 
When the mating pairs have joined, the male of the pair is always 
the one called upon to repel attackers, the female usually sitting on the 
ball during the fight. In only one instance was I able to observe 1 a 
successful robbery, the usurper making off with both the ball and the 
female of the other male. 
The fighting movements involve primarily the head, which is used 
to butt, that is to say, to push upward and outward against the 
opponent. Each antagonist attempts to place the edge of its head under 
some part of the body of the opponent and then quickly jerk it upward. 
If successful, this procedure flips the opponent away and onto its 
back. The defender of a ball always has the advantage because it 
can use the ball to protect its underside by clinging closely to it, 
hence the small number of successful robberies. In addition to the 
head, all the legs are often used and the beetles may grapple together. 
Fights are of very brief duration and apparently do not result in any 
injury to the participants. 
To summarize, the typical situation at a cow dropping during the 
reproductive season is as follows. A few males and pairs are making 
balls and several males are roving about trying to steal a ball rather 
than make one. These males are repulsed by the males of the pairs 
