Is mother condition related to offspring condition in migratory caribou (Rangifer tarandus) at calving and weaning?

• Main Authors: Taillon, Joëlle, Brodeur, Vincent, Festa-Bianchet, Marco, Côté, Steeve D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: National Research Council 2012
• Subjects: psy; anthro-se; Canada; Rivière aux Feuilles; Rivière George; Rangifer tarandus
• Online Access: https://hdl.handle.net/20.500.11794/40366

Maternal characteristics can affect offspring traits, yet they are seldom included when considering density dependence of juvenile traits and population dynamics. We quantified the influence of population size and maternal traits on body condition of migratory caribou (Rangifer tarandus (L., 1758)) calves at birth and weaning. We contrasted female–calf pairs of the Rivière-George (RG) herd, which has recently declined to low population size, with pairs of the much larger Rivièreaux-Feuilles (RAF) herd. Calves of the RAF herd were lighter, smaller, and leaner than calves of the RG herd at both birth and weaning. Differences between herds, however, were much greater at weaning than at calving, suggesting a combined effect of herd size and summer range conditions on calf growth. Maternal mass was positively related to calf body condition during both periods. The positive influence of maternal mass on calf body condition was greater for RAF than RG calves at birth, but it was similar for the two herds at weaning. Our results show that the negative effect of population size on calf body condition can be modulated by maternal mass at calving, and that the positive effect of maternal mass is greater at weaning. Les caractéristiques maternelles peuvent influencer les traits de leur progéniture, mais sont rarement considérées lors de l’étude des effets de la densité sur les traits des juvéniles et la dynamique des populations. Nous avons évalué l’influence de la taille de population et des caractéristiques maternelles sur la condition physique des faons du caribou migrateur (Rangifer tarandus (L., 1758)) à la mise bas et au sevrage. Nous avons comparé des paires de femelle-faon du troupeau Rivière-George (RG) dont la taille de population a récemment décliné, à des paires du troupeau Rivière-aux-Feuilles (RAF) qui est présentement à taille de population élevée. Les faons du RAF présentaient une masse corporelle, une taille corporelle et un indice de gras des reins inférieurs aux faons du RG tant à la mise bas qu’au ...