Self referencing in hamsters: Reply from Hauber & Sherman

Abstract

Mateo and Johnston's study 1xKin recognition and the ‘armpit effect:’ evidence of self-referent phenotype matching. Mateo, J.M and Johnston, R.E. Proc. R. Soc. London B Biol. Sci. 2000; 267: 695–700CrossrefSee all References1 is important for three reasons. First, they devised a novel methodology to untangle the effects of social learning and self-referencing in the ontogeny of kin recognition. They cross-fostered single golden hamster pups <12 hrs after birth, so that each individual had only itself as a source of information about how genetic relatives would smell. By using three separate families, Mateo and Johnston created groups that were, to each cross-fostered pup, familiar non-kin, unfamiliar kin, or unfamiliar non-kin. Previous cross-fostering protocols, which involved rearing juveniles with littermates or their mother 2.xKin recognition in golden hamsters: evidence for phenotype matching. Heth, G et al. Anim. Behav. 1998; 56: 409–417Crossref | PubMed | Scopus (78)See all References, 3.xThe ontogeny of kin recognition in two species of ground squirrels. Holmes, W.G and Sherman, P.W. Am. Zool. 1982; 22: 491–517See all References, confounded familiarity and self-referencing because recognition cues could have been learned from associates, self, or both 4xSocial learning and kin recognition. Alexander, R.D. Ethol. Sociobiol. 1991; 12: 387–399Scopus (15)See all References4. Only by preventing subjects from becoming familiar with the phenotypes of genetic relatives can the two mechanisms be disentangled.Second, Mateo and Johnston found that cross-fostered females approached flank-gland odors of unfamiliar non-kin significantly faster than they approached odors of unfamiliar siblings. This indicates that these hamsters used their own smell as a standard against which to compare novel odors, that is, self-referent phenotype matching.Third, Mateo and Johnston found that cross-fostered hamsters investigated odors of familiar non-kin more slowly and for less time than they investigated odors of unfamiliar non-kin, indicating that the animals had also learned recognition cues from foster littermates. We see no reason why self-matching and familiarity-based mechanisms are incompatible 3xThe ontogeny of kin recognition in two species of ground squirrels. Holmes, W.G and Sherman, P.W. Am. Zool. 1982; 22: 491–517See all References3. To determine the relative importance of the two sources of cues, Mateo and Johnston compared the behavior of females toward odors of unfamiliar sisters and unfamiliar sisters of foster littermates. Test subjects investigated odors of unfamiliar sisters significantly longer, suggesting differential weighting of their own odors over those of their foster family. We cannot comment on the direction of the specific response measures because cues learned from nestmates and self could be used in different recognition contexts 3xThe ontogeny of kin recognition in two species of ground squirrels. Holmes, W.G and Sherman, P.W. Am. Zool. 1982; 22: 491–517See all References3, and the functions of hamster kin recognition in nature are unknown 1.xKin recognition and the ‘armpit effect:’ evidence of self-referent phenotype matching. Mateo, J.M and Johnston, R.E. Proc. R. Soc. London B Biol. Sci. 2000; 267: 695–700CrossrefSee all References, 5.xThe armpit effect in hamster kin recognition. Hauber, M.E and Sherman, P.W. Trends Ecol. Evol. 2000; 15: 349–350Abstract | Full Text | Full Text PDF | PubMed | Scopus (16)See all References.We hope that future lab studies of self-referencing adopt Mateo and Johnston's methodology, and that this exchange encourages field studies of when and why hamsters recognize relatives.