Activity patterns of African elephants in nutrient-rich and nutrient-poor savannas

Mramba, Rosemary Peter; Andreassen, Harry P.; Mlingi, Valeri; Skarpe, Christina

doi:10.1016/j.mambio.2018.12.001

Cited by 12 publications

(8 citation statements)

References 83 publications

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“…Regardless of whether this explanation will stand further scrutiny, it again emphasizes that predictions based on simple allometric physiological rules are probably too simplistic. Another example on habitat specificity as explanation for variable activity levels (Mramba et al, 2019) comes from comparing our elephant activity data with those of previous studies. The LMNP elephants showed low proportional activity levels (0.54-0.68) compared to other studies that report proportional activity levels of 0.75 (Hendrichs, 1971;Wyatt & Eltringham, 1974) or even greater than 0.75 (Gravett et al, 2017).…”

Section: Notementioning

confidence: 83%

Camera‐trap data do not indicate scaling of diel activity and cathemerality with body mass in an East African mammal assemblage

Clauss

Scriba

Kioko

et al. 2021

Ecology and Evolution

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Diel activity patterns, that is, the times when animals are active over the course of the day (e.g., circadian rhythms) and how much they are active over the course of the day (activity level), are fundamental aspects of animal behavior (Daan & Aschoff, 2001;Halberg, 1960).How animals distribute their diel activity and the duration of time during which they are active during the day largely reflect their interactions with food resources, potential mates, predators, and competitors. In their evolutionary histories, mammalian faunivores have generally shifted toward nocturnality and mammalian herbivores toward diurnality (Wu et al., 2018).Diel activity patterns of animals can be classified into diurnal, nocturnal, crepuscular, or cathemeral (Bennie et al., 2014), and the quantitative information on which these categories are based can be gained from camera-trap data (Rowcliffe et al., 2014). Although

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Section: Notementioning

confidence: 83%

Camera‐trap data do not indicate scaling of diel activity and cathemerality with body mass in an East African mammal assemblage

Clauss

Scriba

Kioko

et al. 2021

Ecology and Evolution

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“…food deprived fish leading shoals 43 , lactating zebra mares, Equus burchellii , leading groups to water 44 ). Various studies suggest that smaller bodied adolescents have greater drinking needs 45 , and require higher quality forage relative to older males 46 , 47 ; suggesting that younger adolescents should be the most motivated to travel at the front of groups in order to reach foraging and drinking locations connected by pathways. Such patterns were not observed in the current study, suggesting internal condition was not the key determinant of which individuals arose as leaders in groups.…”

Section: Discussionmentioning

confidence: 99%

Importance of old bulls: leaders and followers in collective movements of all-male groups in African savannah elephants (Loxodonta africana)

Allen

Brent

Motsentwa³

et al. 2020

Sci Rep

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In long-lived social species, older individuals can provide fitness benefits to their groupmates through the imparting of ecological knowledge. Research in this area has largely focused on females in matrilineal societies where, for example, older female African savannah elephants (Loxodonta africana) are most effective at making decisions crucial to herd survival, and old post-reproductive female resident killer whales (Orcinus orca) lead collective movements in hunting grounds. in contrast, little is known about the role of older males as leaders in long-lived social species. By analysing leadership patterns of all-male African savannah elephant traveling groups along elephant pathways in Makgadikgadi pans national park, Botswana, we found that the oldest males were more likely to lead collective movements. our results challenge the assumption that older male elephants are redundant in the population and raise concerns over the biased removal of old bulls that currently occurs in both legal trophy hunting and illegal poaching. Selective harvesting of older males could have detrimental effects on the wider elephant society through loss of leaders crucial to younger male navigation in unknown, risky environments. During coordinated group movements certain individuals can consistently arise as "leaders" with a regular influence over group decisions, with high dominance rank 1 , bold temperament 2 and greater age (often associated with enhanced knowledge or experience 3) noted as common traits characterising leaders (for review, see 4). Whilst in some cases leadership can be a passive process, a consequence of simple consensus decisions to maintain group cohesion 5 , in other cases leaders actively communicate their intent to recruit followers 6. In long-lived species, older individuals often respond more appropriately to complex, changing environments 7,8 , providing substantial fitness benefits to younger group mates. For example, older matriarchs are more effective at mobilising groups in response to predation threats and conspecifics in female African savannah elephants (Loxodonta africana) 8,9 , Similarly, in resident killer whale (Orcinus orca) groups there is a greater reliance on older, post-menopausal females as leaders of hunting groups in years of low salmon abundance 10. Non-human research in this area has tended to focus on females and less attention has been given to the potential for old males to act as repositories of ecological knowledge and leaders in long-lived social species. In many social mammals, males are often assumed to be replaceable because they are typically the dispersing sex 11 , and old males may be reproductively redundant, which is commonly used as an argument to support the legal trophy hunting of old males in many species 12,13. This combined with desirable features such as larger body size and ornaments, leads to selective harvesting of older males in many species, including the African savannah elephant 14. However, there is no reason to believe there would be sex-based differe...

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“…Seasonal variation in the activity budget has been widely reported in primates, including our study species (vervet monkeys: Isbell & Young, 1993) and other species (deers: Pagon et al, 2013; alpine chamois: Brivio et al, 2016; bottleose dolphins: Vermeulen et al, 2015; African elephants: Mramba et al, 2019). During winter (i.e., the dry season in the southern part of Africa), food is scarcer and days are shorter and vervet individuals usually spend a greater proportion of time feeding and less time resting, while time spent moving or involved in social activities may show less consistent patterns (Isbell & Young, 1993; Nakagawa, 2000; Barrett, 2005; but see van Doorn et al, 2010).…”

Section: Introductionmentioning

confidence: 53%

Vervet monkeys socialize more when time budget constraints are experimentally reduced

et al. 2021

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In species that live in stable groups, successful management of time budget (i.e., the proportion of time involved in different behaviours) and social relationships has been proposed to be a key variable affecting individual fitness. Such management is limited by time constraints, which are group size and season dependancy. However, the link between time budget constraints and grooming patterns as a means to service social relationships has never been studied experimentally. Here, we reduced the time constraints of three wild vervet monkey (Chlorocebus aethiops pygerythrus) groups by offering them high quality food for 60 min in the morning. We conducted 10 trials in summer and 10 trials in winter. We found that vervet monkeys indeed reduced the proportion of time spent foraging during the rest of those days compared to control days and increased the proportion of grooming time spread over more bouts. Individuals that did not get access to the food still participated as much in grooming as those that did eat. In accordance with our expectations, social network analysis revealed a larger grooming network on supplementation days: vervet monkeys used their extra time to socialize with more different group members. Furthermore, following our predictions, the effect of provisioning was usually stronger during the winter season (when food was scarce and days shorter) than during the summer, and the number of conflicts decreased during supplementation days. Finally, despite the fact that adults and juveniles of all three groups increased their proportion of time spent grooming during supplementation days, few group and age differences emerged in the way vervet monkeys manage their time budget. Interestingly, some of these differences seem to be independent of group size. In conclusion, vervet monkeys seize the opportunity to increase the proportion of time spent in social behaviours if time budget constraints are reduced.

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Activity patterns of African elephants in nutrient-rich and nutrient-poor savannas

Cited by 12 publications

References 83 publications

Camera‐trap data do not indicate scaling of diel activity and cathemerality with body mass in an East African mammal assemblage

Camera‐trap data do not indicate scaling of diel activity and cathemerality with body mass in an East African mammal assemblage

Importance of old bulls: leaders and followers in collective movements of all-male groups in African savannah elephants (Loxodonta africana)

Vervet monkeys socialize more when time budget constraints are experimentally reduced

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