HORhlONES
4ND
BEHAVIOR
10,
264-276 (1978)
Estrous Synchrony and Its Mediation Airborne Chemical Communication (Rattus norvegicus) MARTHA
by
K. MCCLINTWK
Department C$ Behavioral Sciences, University qf Chicugo, 5730 Wood/own Avenue, Chicago, Illinois 60637 The estrous cycles of a group of female laboratory rats (Rattus norvegicus) who live together become significantly more synchronized than either the cycles of solitary female rats (P s 0.01) or the cycles of female rrrts randomly selected from different living groups (P s 0.01). Airborne chemical communication between otherwise isolated groups of female rats is sufficient to produce the same level of estrous synchrony found among female rats that are actually living together.
Behavior plays an integral role in the control of female mammalian reproductive physiology. Many studies with this orientation have focused on the level of individual behavior and examined the effect of a conspecific male on the timing of estrus (Whitten, Bronson, and Greenstein, 1968; Schinckel, 1954; Thiebault, Courit, Martinent, Mauleon, du Mesnil du Buisson, Ortavant, Pelletier, and Signoret, 1966), ovulation (Cross, 1972; Gray, Davis, Zerylnick, and Dewsbury, 1974), the progestational state (Adler, 1969), puberty (Vandenbergh, 1967), and pregnancy (Bruce, 1959). Studies focused on the level of social behavior have shown that the social pathology of overcrowding is stressful enough to disrupt ovarian function (Calhoun, 1962a; Christian, 1960), while ovarian cyclicity of the laboratory rat is enhanced when female hamsters are present in the same room (Weizenbaum, McClintock. and Adler, 1977). However, little is known about the role of social context and particularly female-female interactions in the successful regulation of normal ovarian physiology. One example of this kind of social control over individual physiology is the synchronization of menstrual cycles among women who live together (McClintock, 1971). This ovarian synchrony in humans is a qualitatively different phenomenon from the synchrony previously reported in female mice (Whitten, 1958) or hamsters (Gross, 1977). The synchrony of the Whitten effect is externally generated by the experimenter who simultaneously releases a group of female mice from ovarian suppression with 264 Copyright All rights
,c 1978 by r\cademic hess. Inc. of reproduction in any form rescrvcd.
the presentation of a male or his urine. The menstrual synchrony reported among women (McClintock, 1971) develops spontaneous1.y over time among the ongoing normal menstrual cycles of a group without induction by an external synchronizer. It therefore demonstrates an effect of z female social structure on the timing of individual menstrual cycles within the group. A parallel study of ovarian synchrony in the Norway rat {Ram!s norbl
4ND
BEHAVIOR
10,
264-276 (1978)
Estrous Synchrony and Its Mediation Airborne Chemical Communication (Rattus norvegicus) MARTHA
by
K. MCCLINTWK
Department C$ Behavioral Sciences, University qf Chicugo, 5730 Wood/own Avenue, Chicago, Illinois 60637 The estrous cycles of a group of female laboratory rats (Rattus norvegicus) who live together become significantly more synchronized than either the cycles of solitary female rats (P s 0.01) or the cycles of female rrrts randomly selected from different living groups (P s 0.01). Airborne chemical communication between otherwise isolated groups of female rats is sufficient to produce the same level of estrous synchrony found among female rats that are actually living together.
Behavior plays an integral role in the control of female mammalian reproductive physiology. Many studies with this orientation have focused on the level of individual behavior and examined the effect of a conspecific male on the timing of estrus (Whitten, Bronson, and Greenstein, 1968; Schinckel, 1954; Thiebault, Courit, Martinent, Mauleon, du Mesnil du Buisson, Ortavant, Pelletier, and Signoret, 1966), ovulation (Cross, 1972; Gray, Davis, Zerylnick, and Dewsbury, 1974), the progestational state (Adler, 1969), puberty (Vandenbergh, 1967), and pregnancy (Bruce, 1959). Studies focused on the level of social behavior have shown that the social pathology of overcrowding is stressful enough to disrupt ovarian function (Calhoun, 1962a; Christian, 1960), while ovarian cyclicity of the laboratory rat is enhanced when female hamsters are present in the same room (Weizenbaum, McClintock. and Adler, 1977). However, little is known about the role of social context and particularly female-female interactions in the successful regulation of normal ovarian physiology. One example of this kind of social control over individual physiology is the synchronization of menstrual cycles among women who live together (McClintock, 1971). This ovarian synchrony in humans is a qualitatively different phenomenon from the synchrony previously reported in female mice (Whitten, 1958) or hamsters (Gross, 1977). The synchrony of the Whitten effect is externally generated by the experimenter who simultaneously releases a group of female mice from ovarian suppression with 264 Copyright All rights
,c 1978 by r\cademic hess. Inc. of reproduction in any form rescrvcd.
the presentation of a male or his urine. The menstrual synchrony reported among women (McClintock, 1971) develops spontaneous1.y over time among the ongoing normal menstrual cycles of a group without induction by an external synchronizer. It therefore demonstrates an effect of z female social structure on the timing of individual menstrual cycles within the group. A parallel study of ovarian synchrony in the Norway rat {Ram!s norbl
