Geoscience Reference
In-Depth Information
males groom a female in order to gain the opportunity to sniff her nasoanal
region and, ultimately, to decrease her tendency to flee, thereby allowing them
the opportunity to mate. Females are most likely to mate with males that
groom them the most. This constitutes an unusual example of the market
effect (Noe et al. 1991) in a short-lived mammal, with females essentially sell-
ing sex in exchange for grooming.
Allogrooming is the clearest and most common form of cooperation
among badgers. It appears to be a valuable supplement to self-grooming be-
cause it is focused on the parts of a badger (back of neck, shoulders, and upper
rump) that are most difficult for an individual to reach for itself (Stewart 1997;
Stewart and Macdonald, unpublished data). The proportion of grooming
directed to each segment of the body differs, but is complementary between
self-grooming and allogrooming (figure 10.2).
Allogrooming cooperation is maintained in this case by the simple expedi-
ent of ensuring that as much grooming is given as received. Adult badgers
groom one another simultaneously using a responsive rule set (Axelrod and
Hamilton 1981) that dictates that grooming can be initiated generously, but
rapidly withdrawn (at a mean of just 1.2 seconds) if the recipient does not
respond in kind. If the recipient reciprocates, then the two badgers groom each
Figure 10.2
Silhouettes represent the proportion of time, per square centimeter, spent grooming
different portions of the body surface. It shows that although self-grooming or allogrooming alone is
strongly biased toward particular body regions, a combination of self-grooming and allogrooming
produces a fairly even body coverage. This supports a generally utilitarian function for badger groom-
ing. The slight overrepresentation of the shoulder is the result of that being the most common site of
grooming initiation during greeting, indicating an additional social function or a necessary social eti-
quette during such cooperative relations. R = rump, S = side, H = head, T = tail, B = belly, C = chest.
