The Role of Non‐reproductive Helpers in Infant Care in Captive Callithrix jacchus

Abstract

Callitrichids have been proposed as communal breeders, with non-reproductive animals acting as helpers. Reports in the literature attest to the high variability in the behaviour of helpers. The present study assessed four proximate factors involved in helping in captive Cullitbrix~uccbuJ: age, gender and experience of helpers and composition of their groups. Forty-eight helpers from 15 families from Natal (Brazil) and Reading (UK) colonies were observed during the first 4 weeks of life of new-born twins. Infant carrying, transfers and retrieval, and duration of carrying bouts were registered. Results showed that the presence of helpers decreased the costs of infant carrying, with a negatively significant correlation between group size and mean percentage of carrying. Age, but not gender, was a significant factor for infant carrying, transfers and retrieval, and mean duration of carrying bouts, with older helpers contributing more than younger ones. Singletons and oldest non-reproductive offspring carried infants more, and longer, than twins and offspring with older siblings present in the group. Experience decreased motivation and actual carrying time, but not to a significant level. Age, experience and group composition appeared important factors in the display of infant care by helpers in captive CuLlitbtixjaccbus.

Oxytocin is associated with infant-care behavior and motivation in cooperatively breeding marmoset monkeys

“…Nevertheless, caretakers also compete over access to infants (Mills et al, 2004;Yamamoto and Box, 1997;Zahed et al, 2010), and particularly female helpers are not always tolerated by other group members to handle and carry infants as much as they attempt to (Albuquerque, 1999;Price, 1991). Hence, individual infant-carrying contributions may not necessarily correspond to intrinsic motivational levels, especially if more care-takers than infants are available.…”

Differential infant carrying in captive and wild common marmosets (Callithrix jacchus)

“…This is probably a consequence of larger groups and, therefore, more helpers available in wild groups. Such bias has never been reported in the literature, although there have been reports that male helpers carry infants more than do females in both captive (Rothe and Darms 1993; but see Yamamoto and Box 1997) and wild C. jacchus groups (Albuquerque 1999). This same bias regarding the sex of helpers had been reported before for wild Saguinus mystax (Garber et al 1984).…”

“…These primates lack sexual dimorphism and only a few studies have examined gender differences among them (Box 1999;Box et al 1995Box et al , 1999Goldizen et al 1996). Price (1992) and Yamamoto and Box (1997) have examined the influence of the caregivers' sex on the contribution to infant care, but to date, no studies have reported differences in care related to the infants' sex. Goldizen et al (1996) showed that female Saguinus fuscicollis have a higher variation in lifetime reproductive success than that of males, given the paucity of female breeding positions, the brief mean tenure time and the apparently higher mortality rate for females at reproductive age.…”

Food Sharing in Lion Tamarins (Leontopithecus chrysomelas): Does Foraging Difficulty Affect Investment in Young by Breeders and Helpers?

“…(Tardif et al 1993). In these latter species, fathers and helpers play a conspicuous role in offspring care (Washabaugh et al 2002;Yamamoto and Box 1997). If our reasoning is accurate, the fathers in marmosets and groups of Saguinus spp.…”