Cooperative Breeding and its Significance to the Demographic Success of Humans

Abstract

AN39CH25-Kramer ARI

Ecological Knowledge, Leadership, and the Evolution of Menopause in Killer Whales

“…There is mounting evidence that menopause evolved via inclusive fitness benefits gained by helping kin; both postreproductive humans [11][12][13][14] and killer whales [15] increase the reproductive success and/or survival of their relatives. But how postreproductive females help their kin remains enigmatic.…”

Does grandparental help mediate the relationship between kin presence and fertility?

“…However, the large-scale datasets often used to demonstrate associations between kin availability and fitness outcomes are typically not suitable for testing whether such associations are driven by help from kin: usually an association between some measure of kin presence and a fitness outcome is all that is demonstrated (see exceptions : Waynforth 2012;Mathews and Sear 2013;Kaptijn et al 2010). There is a parallel literature, from anthropologists working in small-scale subsistence societies, which has clearly demonstrated that kin do provide alloparenting and other forms of help for one another (Gibson and Mace 2005;Hawkes, O'Connell, and Blurton Jones 1997;Ivey 2000;Kramer 2010;Meehan, Quinlan, and Malcom 2013). This supports the argument that kin help may be the cause of associations between kin and reproductive outcomes, but sufficiently detailed time−budget data are difficult to collect, so that it is rare to find datasets detailed enough to directly test whether kin help influences fitness outcomes.…”

When Dads Help: Male Behavioral Care During Primate Infant Development

“…In most human societies, mothers are not the sole caretakers of infants, and fathers, other relatives, and even unrelated individuals may participate in infant care (Geary 2005 ;Hewlett 1989 ;Hrdy 2008 ;Kramer 2010 ;Marlowe 2000 ) . Direct male care is facultative for our species and can range from being virtually absent to providing a substantial contribution to a child's upbringing.…”