Higher maternal care and tolerance in more experienced giraffe mothers
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.
KeywordsParity Female Age Maternal Care Terminal investment Reproductive effort Allonursing
We would like to express our gratitude to zoo managers and staff for cooperation during the data collection, especially Jaroslav Šimek, Barbora Dobiášová and Jan Marek from Prague Zoo, Libuše Veselá from Olomouc Zoo, Luděk Čulík from Safaripark Dvůr Králové and Luboš Melichar from Liberec Zoo. We are thankful to Francisco Ceacero Herrador for his help with Akaike weights and also Radka Šárová for her comments during data processing. We gratefully acknowledge Sarah R. B. King for improving the English.
This work was supported by the Ministry of Agriculture of the Czech Republic (MZERO0714) CIGA 20185008 and IGA 20185021.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
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