Rodent Societies: An Ecological & Evolutionary Perspective

meyer 1988a). For example, Spermophilussocial organiza-
tion forms a continuum ranging from relatively asocial spe-
cies (e.g., S. tridecemlineatus) to relatively social species
(e.g., S. richardsonii, S. beldingi,and S. parryi), and it was
thought that this variation could be used to predict inter-
specific differences in recognition abilities and mechanisms
(table 2 in Sherman and Holmes 1985). More recent work,
however, calls into question some of the expected links be-
tween sociality and kin-recognition abilities (Hare and Mu-
rie 1996), as seen, for example, in a comparison between

recognition abilities in a relatively social species,S. beldingi,

with a relatively asocial species, S. lateralis. Despite these

differences in sociality, juveniles in both species display sim-

ilar social preferences for littermates over nonlittermates

and are able to recognize unfamiliar kin when they are first

encountered (Holmes 1995). Considering the production

component, both species produce odors that can be used

to discriminate among classes of kin like siblings, paternal

half-siblings, and grandmothers, but only S. beldingibe-

haves nepotistically to kin other than offspring. Kin labels

Kin Recognition in Rodents: Issues and Evidence 223

Figure 19.4 The time spent by Spermophilus beldingisubjects investigating the odors of subjects’ unfamiliar (never encoun-

tered) relatives during olfactory preference tasks. (A) Investigation of oral-gland odors of unfamiliar kin, collected from sub-

jects’ 3/4th sibling (offspring of two sisters mated with the same male), cousins (offspring of a subject’s mother’s brother) and

nonkin. (B) Investigation of oral-gland odors collected from subjects’ grandmothers and aunts. (C) Investigation of dorsal-gland

odors collected from subjects’ half aunt (mother’s half sister) and nonkin. Numbers inside bars are estimated coefficients of

relatedness (due to mixed paternity within litters) between subjects and odor donors. Horizontal bars and asterisks represent

significant differences in investigation times (* p0.05, ** p0.01). Increased investigation time as relatedness of the odor

donor to the subject decreases indicates that odors of distant kin are perceived as less familiar to subjects than odors of close

kin. Significant differences in investigation of odors from various kin classes indicate discrimination of those odors, and thus

that the subject can recognize the difference between, for example, its distant kin and nonkin (figures 19.4a and 19.4c).

(A)

(B) (C)