The ability of naked mole-rats, Heterocephalus glaber, to discriminate
between familiar and unfamiliar conspecifics and their response to in
truders was investigated. Odour cues used by mole-rats in recognition
contexts were identified in a three-way choice apparatus and 'decision
rules' for accepting or rejecting conspecifics were explored in a ser
ies of odour manipulation experiments. Naked mole-rats were highly xen
ophobic, even to closely related foreign conspecifics, and a division
of labour existed amongst the non-breeders in colony defence. The prin
cipal mechanism of recognition appeared to be distinct colony odour la
bels, contributed by each colony member and distributed among, and lea
rned by, all colony members. Differences in the mixture of these odour
s may provide even genetically similar colonies with a unique odour la
bel. These odours persisted despite controlling for exogenous cues. Fi
tness consequences of these phenomena are interpreted with respect to
the need for closely related neighbouring colonies to maintain autonom
y and the importance of excluding foreign competitors from within-colo
ny rivalry for reproductive succession. (C) 1997 The Association for t
he Study of Animal Behaviour.