The Havers-Halberg oscillation regulates primate tissue and organ masses across the life-history continuum

Long period biological timing, as deduced from a primate enamel formation rhythm termed the repeat interval (RI), varies predictably with body size and primate life-history characteristics. RI is a manifestation of a fundamental metabolic rhythm termed the Havers-Halberg oscillation (HHO). Because body size is highly associated with RI (and the HHO), we assume that RI should also have relationships with primate tissue and organ masses that likely covary with body size. We evaluate body mass and constituent tissue and organ masses, as well as basal metabolic rate (BMR), for twelve primate taxa. Regressing RI against tissue, organ, and body masses, as well as BMR, we find the relationships to be significant. Partial correlations controlling for the effects of either body mass or fat-free body mass suggest that the significant associations that tissue and organ masses have with each other are likely related to their dependence on body size in general. Body mass and most tissue masses approximate 1/4 scaling. However, brain mass has a singularly high slope in relation to RI. The relatively slow growth of other tissue and organ masses with increasing RI may provide 'payment' for the high mass specific metabolic rate of the brain.