The dear enemy effect has been explained in terms of familiarity (individuals learn who their neighbors
are, and as they become familiar with these others, they become less aggressive toward them). An alternative explanation can be labeled the threat level hypothesis, which states that the dear enemy effect
results from the reduced threat to the fitness of a territory holder offered by neighbors that no longer challenge the territory owner next door. Could both of these hypotheses be right? The banded mongoose
(Mungos mungo) is a group-living, territorial mammal in which individuals react more aggressively to members of neighboring bands than to strangers (Müller and Manser 2007). If the threat level hypothesis
is right, what prediction can you make about the nature of interactions between two neighboring bands versus the band and an intruding stranger?