Old grandmothers provide essential care to their young granddaughters in a free-ranging group of Japanese monkeys (Macaca fuscata)

Nakamichi, Masayuki; Onishi, Kyosuke; Yamada, Kazunori

doi:10.1007/s10329-009-0177-7

Cited by 16 publications

(7 citation statements)

References 9 publications

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“…Assorting by reproductive state may also reduce infant mortality and confer other benefits. Offspring survival is increased by multiple carers (Clutton‐Brock et al 2001, Silk et al 2003, Silk 2007a, Cheney et al 2016) and the close proximity of their grandmother (Hawkes et al 1998, Alvarez 2000, Nakamichi et al 2010, Brent et al 2015, Lahdenperä et al 2016); both mother and offspring benefit when the mother has strong and consistent bonds with other females (Cameron et al 2009, Silk et al 2009, 2010). Close social networks can also influence other factors related to survival, e.g.…”

Section: Discussionmentioning

confidence: 99%

A review of the social behaviour of the giraffeGiraffa camelopardalis: a misunderstood but socially complex species

Raw

2021

Mammal Review

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1. Until around 2000, giraffe Giraffa camelopardalis were believed to have no social structure. Despite a resurgence of interest in giraffe behaviour in around 2010, most studies are of isolated populations, making it difficult to draw general conclusions. Although it is now well established that giraffe social organisation is non-random, there is little consensus as to what influences preferred and avoided associations or the underpinning mechanisms. 2.We test two hypotheses: first, giraffe have a complex cooperative social system, exhibited by 1) stable groups of females, 2) offspring that stay in their natal group for part or all of their lives, 3) support by non-mothers in rearing young, and 4) non-reproductive females in the group; and second, giraffe form matrilineal societies, evidenced by 1) male dispersal, 2) female philopatry, 3) assistance in raising or protecting offspring, and 4) individual benefits gained from social foraging. 3. We reviewed 404 papers on giraffe behaviour and social organisation; captive studies were included where they supplemented information from free-living populations. 4. We show that giraffe exhibit many of the features typical of mammals with complex cooperative social systems and matrilineal societies. However, the social complexity hypothesis posits that such species also require complex communication systems to regulate interactions and relations among group members; giraffe communication systems are poorly understood. 5. Quantifying the fitness and survival benefits of the giraffe's social organisation is necessary to ensure its long-term survival. Giraffe numbers have declined by 40% since 1985, they have been declared extinct in seven (possibly nine) countries and are listed as Vulnerable by the International Union for Conservation of Nature. We identify research areas that will advance our understanding of giraffe behaviour and conservation requirements.

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Section: Discussionmentioning

confidence: 99%

A review of the social behaviour of the giraffeGiraffa camelopardalis: a misunderstood but socially complex species

Raw

2021

Mammal Review

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“…However, the genetic relationship of the older females to the younger individuals is often unknown, and thus little can be concluded with certainty about the fitness effects of grandmothers. Also, while the evidence of singular cases of a helping grandmother is large151617, the evidence of measurable fitness effects of grandmothers in non-menopausal taxa comes from only a few species. The presence of grandmothers increased the survival of grandoffspring in vervet monkeys ( Chlorocebus aethiops sabaeus )18 and Japanese macaques ( Macaca fuscata )19.…”

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confidence: 99%

Nearby grandmother enhances calf survival and reproduction in Asian elephants

Lahdenperä

Mar

Lummaa

2016

Sci Rep

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Usually animals reproduce into old age, but a few species such as humans and killer whales can live decades after their last reproduction. The grandmother hypothesis proposes that such life-history evolved through older females switching to invest in their existing (grand)offspring, thereby increasing their inclusive fitness and selection for post-reproductive lifespan. However, positive grandmother effects are also found in non-menopausal taxa, but evidence of their associated fitness effects is rare and only a few tests of the hypothesis in such species exist. Here we investigate the grandmother effects in Asian elephants. Using a multigenerational demographic dataset on semi-captive elephants in Myanmar, we found that grandcalves from young mothers (<20 years) had 8 times lower mortality risk if the grandmother resided with her grandcalf compared to grandmothers residing elsewhere. Resident grandmothers also decreased their daughters’ inter-birth intervals by one year. In contrast to the hypothesis predictions, the grandmother’s own reproductive status did not modify such grandmother benefits. That elephant grandmothers increased their inclusive fitness by enhancing their daughter’s reproductive rate and success irrespective of their own reproductive status suggests that fitness-enhancing grandmaternal effects are widespread, and challenge the view that grandmother effects alone select for menopause coupled with long post-reproductive lifespan.

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“…Our finding that adolescent giraffes display strong associations with other adolescents of their own sex, and then with adults of their own sex, demonstrates that the period of adolescence in giraffes shares similar features to adolescence in other mammal species (Evans and Harris 2008;Clutton-Brock and Lukas 2012;Sisk 2016). Adolescence may be a period in which giraffes associate closely with others to facilitate learning social skills and information about the resources in their environment, and potentially build bonds and relationships to carry through to adulthood Berry 2010, 2013b;Carter et al 2013a), as suggested in other mammals (Nakamichi et al 2010;Brent et al 2015;Lahdenperä et al 2016).…”

Section: Discussionmentioning

confidence: 99%

Adolescence and the development of social behaviour in giraffes

Raw

Cuthill

2022

Mamm Biol

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All mammals experience different life stages as they develop, each of which is characterised by particular physical and behavioural changes. Despite the emergence of sophisticated behaviour analysis techniques, the ways in which social behaviour varies by life stage, and how this is influenced by an individual’s sex, is relatively understudied in most social mammals other than primates and elephants. Understanding the social requirements of mammals should be a central and critical component to their conservation, captive management and welfare. Here, we apply social network analysis techniques to understand how social behaviour differs with life stage in the giraffe, a gregarious fission–fusion mammal. We studied two wild populations of giraffes in Kenya and found that adolescents have significantly stronger associations with adolescents of their own sex first and foremost, then adults of their own sex. Other associations were significantly lower than would be expected, or non-significant. Our results suggest that adolescence in both male and female giraffes shares similar features to adolescence in other social mammal species. We discuss how the application of such knowledge might improve the management and welfare of captive giraffes.

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Old grandmothers provide essential care to their young granddaughters in a free-ranging group of Japanese monkeys (Macaca fuscata)

Cited by 16 publications

References 9 publications

A review of the social behaviour of the giraffeGiraffa camelopardalis: a misunderstood but socially complex species

A review of the social behaviour of the giraffeGiraffa camelopardalis: a misunderstood but socially complex species

Nearby grandmother enhances calf survival and reproduction in Asian elephants

Adolescence and the development of social behaviour in giraffes

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