|Author(s)||Markéta Gloneková, Karolína Brandlová and Jan Pluháček|
Maternal investment and maternal care provided by mammalian females can change during their ontogeny. Differences may be related to the age and/or experience (parity) of the female. Several hypotheses have been postulated to explain changes in the rate of maternal care of females during their lifetime. The residual reproductive value hypothesis supposes a higher rate of maternal care in older and more experienced females, in contrast the targeted reproductive effort hypothesis predicts lower levels of maternal care in older and/or more experienced females. To test these hypotheses we investigated nursing bout frequency and time devoted to nursing as predictors of the rate of maternal care, and rate of successful nursing bouts as a predictor of maternal investment, in captive giraffe (22 females, 47 calves in four zoos). We also considered the high rate of allonursing (nursing of non-filial calves) which appeared in all herds. The nursing and allonursing bout frequency as well as the total time devoted to nursing and allonursing increased with increasing parity and age of the female, thus supporting the residual reproductive value hypothesis. In addition, maternal experience of individual females in terms of parity rather than age was responsible for variation in maternal behaviour. This suggests that variation depends on individual experiences.
Keywords: Parity, Female Age, Maternal Care, Terminal investment, Reproductive effort, Allonursing
Authors: Markéta Gloneková, Karolína Brandlová and Jan Pluháček
Journal: acta ethologica