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Older Offspring (older + offspring)
Selected AbstractsSocial learning and mother's behavior in manipulative tasks in infant marmosetsAMERICAN JOURNAL OF PRIMATOLOGY, Issue 6 2009Vera Dell'Mour Abstract High levels of social tolerance are considered to promote social learning, as they allow direct observation of a manipulating conspecific and facilitate scrounging. Owing to tolerance toward infants, infancy is thought to be especially suited for learning socially transmitted behaviors. Despite this, few studies have investigated social learning of infants, particularly in manipulative tasks where observation might be most helpful. Here, we investigated (1) the influence of social learning on task acquisition in infant marmosets, and (2) whether the mother augments her behavior in a way that may enhance social learning by her infants. We tested infant and juvenile marmosets in four different complex foraging-related tasks, featuring large living insects (two tasks) or artificially embedded prey (two tasks). Each individual observed the mother solving two of the tasks and served as a control in the other two tasks. Observers manipulated more and succeeded sooner than control animals, suggesting that observing the mother promoted learning either directly or by decreasing neophobia. Moreover, the data suggest that learning in 11,15 week-old infants might be promoted actively by the mother. She solved the tasks, consumed less food, and consumed it later than when foraging with older offspring or alone. Furthermore, the results indicate the possible importance of the third and fourth month of infancy as the crucial ontogenetic period for social learning in marmosets, corroborating recent observations of free-living common marmosets. Am. J. Primatol. 71:503,509, 2009. © 2009 Wiley-Liss, Inc. [source] Begging for information: mother,offspring food sharing among wild Bornean orangutansAMERICAN JOURNAL OF PRIMATOLOGY, Issue 6 2008Adrian V. Jaeggi Abstract Transfer of solid food from mothers or other adults to dependent offspring is commonly observed in various primate species and both nutritional and informational benefits have been proposed to explain the function of such food sharing. Predictions from these hypotheses are tested using observational data on wild orangutans (Pongo pygmaeus wurmbii) at Tuanan, Central Borneo, Indonesia. In 1,145,hr of focal observation and 458 recorded food interactions between four pairs of females with offspring it was found that virtually all transfers were initiated by the offspring and that younger infants solicited food more often and did so for a greater variety of items than older offspring. All offspring primarily solicited food that was difficult to process, i.e., inaccessible to them. Furthermore, the amount of food solicitation was negatively correlated with ecological competence. Hence food sharing seemed to be related to an offspring's skill level, as suggested by the informational hypothesis. In contrast, offspring did not solicit high-quality items more than low-quality items and food sharing did not peak around the age of weaning, as predicted by the nutritional hypothesis. Mothers were usually passively tolerant, allowing offspring to take food but hardly ever provisioned. Parent,offspring conflict concerning food sharing was only observed well after weaning. Thus, by taking food directly from the mother, young orangutans were able to obtain information about the affordances and nutritional value of food items that were otherwise out of their reach and could familiarize themselves with the mother's diet. In species such as orangutans or other apes, characterized by a broad diet that requires extractive foraging, informational food transfer may be vital for an immature to acquire complex feeding skills and adult diet. Am. J. Primatol. 70:533,541, 2008. © 2008 Wiley-Liss, Inc. [source] Developmental changes in responsiveness to parents and unfamiliar adults in a monogamous monkey (Callicebus moloch)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 2 2002D.J. Mayeaux Abstract Titi monkeys (Callicebus moloch) are monogamous New World primates that are characteristically found in family-type groups consisting of a mated adult pair and one or two young. The factors maintaining the small size of these groups are not known. Based on observations of free-ranging and captive families, parental aggression toward older offspring seems unlikely to play a significant role. Maturing individuals themselves, however, could undergo behavioral changes that weaken ties to their natal group. These might include waning of affiliative relations with parents, or subtle forms of aversion. Independent of such changes, increasing interest in unfamiliar conspecifics could be a factor. We examined these possibilities in the present study by assessing changes in social behavior and social preferences from initial ambulatory independence (6 months) through reproductive maturity (24 months) in a combined cross-sectional/longitudinal study of 21 captive titi monkeys living with their parents. Responses to both parents and to an unfamiliar adult heterosexual pair, a single unfamiliar adult male, and a single unfamiliar adult female were observed when subjects were given a choice between parents and strangers presented simultaneously or as the only social incentive. Social stimuli were at opposite ends of a 16.8-m-long test corridor. Subjects could move freely about the corridor for 5 min with each configuration of social stimuli. They stayed closer to parents than to strangers at all ages. Responsiveness to strangers increased with age and suggested growing ambivalence, particularly toward the male stranger. As they approached 24 months of age, male subjects showed a dramatic increase in the frequency and intensity of agonistic behaviors toward male strangers, behaviors that were rarely directed toward female strangers or parents. Waning of attraction to parents may be less important in dispersal from the natal group than changing reactions to strangers. Am. J. Primatol. 58:71,89, 2002. © 2002 Wiley-Liss, Inc. [source] Influence of hatching asynchrony and within-brood parental investment on size, condition, and immunocompetence in nestling red-billed choughsBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2008EVA BANDA Studies of hatching asynchrony have rarely assessed the effect of parental investment strategies on the development of intra-brood hierarchies using indicators of nestling quality. The influence of hatching asynchrony and other variables related to parental investment on immunocompetence was evaluated measuring T-cell mediated immune response in broods of red-billed choughs (Pyrrhocorax pyrrhocorax), a large long-living passerine with a pronounced sexual size dimorphism. The results showed that T-cell mediated immune response depends on parental effects as shown by the differences between broods on hatching asynchrony. Male nestlings were both heavier and larger than female nestlings, but there was no effect of hatching order on these traits, nor on sex differences in immunocompetence. Differential investment strategy in relation to laying order did not favour older offspring or either of the sexes. Successful reproduction in this species might be so unpredictable and infrequent that strategies of parental investment in the brood could have evolved to attempt to maximize the survival of all nestlings by avoiding within-brood hierachies of size, body condition, and immunocompetence. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 94, 675,684. [source] | ||||||||||